With the introduction of four man queues, and recent Premiere Events, more people are playing 100 Card Singleton every week.  On this site, Tarmotog has done a great job of surveying and analyzing the format.  While I am not yet an expert on 100 Card Singleton, I have been playing my preferred deck, MonoR, in the queues to some success.  In this article, I am hoping to create a reference of all the important cards for the MonoR deck, which should allow you to tailor the deck to your playstyle.

Mana

Before getting to the meat of the article, though, one note on mana-bases.  The biggest advantage of playing MonoR - more than any strategic edge -  is the consistency of the manabase.  In traditional formats, you probably lose 10-20% of your games due to mana-screw or flood.  By playing MonoR in singleton, you keep that percentage in your favor.  A number of singleton decks try to stretch into three or more colors, but even with all of the mana-fixing lands printed throughout the years, they still have difficulties.  I would estimate these decks lose another 10% of their games, simply because they are playing more colors.  These decks justify the risk by trying a win all the games they don't get mana screwed, but that still means that the MonoR deck starts ahead in the matchup, and can further that advantage with selective mana-disruption.

On the same note, it's tempting, given MonoR's easy mana requirements, to play utility lands like Pendelhaven, Shinka, the Bloodsoaked Keep, or Kher Keep.  Don't do that. While these cards can help you, MonoR leans heavily on multi-R cost spells and creatures.  If you insist on playing these cards, consider them 0-mana spells rather than lands.  While Pendelhaven is great when you can tap it for green, it is pretty mediocre when all it does is give your 1/1s a small pump.  Even Shinka has its costs in the deck since so much of the deck revolves around mountains (see below).  At the moment, the only non-Mountain lands I play are Mishra's Factory, Mutavault, Wasteland, Barbarian Ring, Ghitu Encampment, and Forgotten Cave.

Packages

Given the nature of singleton, rather than thinking in terms of individual cards, it can be useful to think of packages, groups of redundant cards that have similar functions.  For MonoR, these packages include:

1-drops
Two+ drops
Mana denial
Burn
Utility creatures (including reusable burn, 187s, etc.)

One drops

The ideal one drop attacks 3-4 times, and deals 3-6 damage before you can sacrifice it for some small gain.  Since this is 100 card singleton, I would recommend playing 10-14 one-drops to try to ensure that you can play a creature on turn one.  I categorize one-drops into three groups: beaters meant to deal as much combat damage as possible; utility creatures that remove blockers, or can burn; and "fanatics" that have interesting sac abilities (listed in each category by my preference):

Figure of Destiny and Grim Lavamancer are obviously superb creatures, but there are a lot of intriguing 1-drops in Magic history.  While Stream Hopper and Goblin Balloon Brigade look terrible at first glance, they can be great in the late game for getting in the last few points of damage.  Similarly, no one wants to block Godo's Irregulars with mana open.  On the fanatic side, Karplusan Wolverine and Duergar Assailant never saw play in sixty card formats, but are still useful since no one wants to trade their two-drops for a "crappy" one drop.  While I would not necessarily play the creatures at the bottom of these lists, you should keep them in mind when considering the strategy of your deck.  If you expect the game to be over by turn five, Magus of the Scroll loses value, and even Raging Goblin may be better than it.  If you are playing a more controlling deck, Stream Hopper may be better than Tattermunge Maniac, since it retains value in later turns.

Two+ drops

After the one drops we have two-drops, and bigger creatures.  One of the huge advantage of playing MonoR is that you have access to hasty creatures.  Haste turns all of your creatures into mini burn spells, since they can get in for damage before being answered.  Haste is often a cheap keyword too, as creatures like Boggart Ram-Gang have three power for three mana.  In order to justify a lack of haste, I believe "sick" creatures need to be extraordinarily large, or bring something else to the table like Countryside Crusher.  I've listed the best Hasty and fat creatures below, in order of mana cost:

Here there are even more options than for one drops.  Depending on how long the game goes, you can tilt the deck towards higher or lower cost creatures.  Furthermore, if you don't love haste as much as I do, you can pick the larger fatties.  Probably my favourite underappreciated creature in this category is Oxidda Golem, which is almost as good as the Ram-Gang.  His affinity for Mountains, along with Arc-Slogger and Fireblast are why I prefer Mountains to card like Stalking Stones.  Speaking of Arc-Slogger, you almost always win the game if he survives in play, since you don't have to worry about running out of cards in your library.  Once you get to four+ mana creatures, I feel like they should each indvidually win the game.  While Arc-Slogger and Siege-Gang Commander are able to do that, I am less excited by Deus of Calamity or Balefire Liege.  Even if you untap with those cards in play, your opponent may still have two or three turns to answer those threats before losing.

Mana denial

As I wrote in the beginning, mana-denial can provide you with some of your easiest wins.  With so many decks running two or more colors, you have the opportunity to both color- and mana-screw your opponent.  Let's list (again in order of preference):

The dwarven twins have been a staple of the singleton format since the beginning.  While they are the best reusable land destruction ever printed, they are also extremely risky and mana intensive.  If your opponent has any sort of mana-fixing, or is playing a mono-colored deck, you may end up paying two mana for a 1/1.  Most of these spells are fairly well-known, althought I was surprised to discover Lava Blister.  Giving your opponents a choice is rarely good, but both options seem good for a red mage.  Finally, if you are feeling lucky, you may want to include Blood Moon or Cryoclasm.  These cards would be auto-includes in any sideboard if the format had them.

Burn

Ah, burn, the reason to play MonoR.  Here is a list of all the burn spells to do as much damage as they cost (plus X spells):

Like the creature section, you have a huge number of options here.  Flame Jab may be great for a long game, but it is not as good as Shock if you're only going to cast it once or twice.  If you are playing a lot of small creatures and want to clear the way, Lash Out or Skred may be better than Volcanic Hammer.  If you're worried about troublesome Kitchen Finks, you can play Carbonize; on the other hand, no blue mage likes to see Sudden Shock or Urza's Rage.  I've included the x-spells in this list, since some people like to have a strong top end.  The downside of any x-spell, though, is that you can never do as much damage as you pay.  My style of MonoR thrives on efficiency over strength.  I also include creatures like Keldon Marauders and Ball Lightning here, since they both exist only to do damage to an opponent.

Utility creatures (and spells)

Finally, we have the spells that serve a slightly different purpose, whether it's to ensure inevitability, deal with lifegain or counterspells:

Reusable burn cards are obviously great for long games, and all of the creature variants have the bonus of being able to swing in for normal damage as well.  While Cursed Scroll was a staple in its time, it requires four mana of investment before you get your first damage, which is quite expensive in this deck.  The 187 creatures speak for themselves,yielding card advantage and pressure (I've never actually played Noggle Hedge-Mage, but it retains some value on a cluttered board).  In the other category, Orcish Librarian is one of my favourite cards.  It acts like an even better Divining Top, in that it includes a shuffle-like effect in its activation, ensuring you continue to get action.  I've rarely lost a game where I was able to activate it multiple times.  The equipment are self-explanatory.

Goblin Package

Besides the traditional groups of cards, I should also mention goblins.  Since so many of the great red cards are already goblins, it is fairly easy to include some force-multiplying goblins.  Since these are all more expensive creatures, you would simply replace your least favourite two+ drops with the cards below.  These cards provide you with a little combo opportunity.

Goblin Grenade
Clickslither (with haste!)
Kiki-Jiki, Mirror Breaker
Goblin Ringleader
Goblin Warchief
Goblin Matron
Goblin Recruiter
Ib-Halfheart, Goblin Tactician (sorta kidding)

A side-by-side comparison

 Having listed so many cards, it might be helpful to do a side-by-side comparison of two MonoR singleton decks.  I have listed below the deck I have been playing in queues, and Tarmotog's deck from his last article (differences listed in bold):

So what is there to learn from these two very long lists?  First, Tarmotog and I take very different approaches to our manabases.  I have a conservative manabase where almost every card generates R, while Tarmotog takes a few more risks.  He includes two Onslaught sac-lands as a bow to his Divining Top, giving him shuffle effects and a little mana-thinning.  I'm guessing his manabase has also effected some of his card selection, like choosing Rorix and Tarox over Demigod of Revenge.

Beyond the manabases, I would say Tarmotog's deck has a slightly higher curve, and may have more late-game staying power.  Our decks are most similar in their one drops, with my deck including a few more of them.  To be honest, my inclusions of Karplusan Wolverine and Stream Hopper have more to do with individuality than strategy.  The rest of our creature bases are quite different, which is unsurprising given the number of options available. Perhaps the one strategic difference between them is that I prefer reusable effects (see Jaya, or the Ravnica Guildmages), while Tarmotog prefers larger creatures like Thunderblust (it appears he may even like haste more than I do).

The differences in the mana denial and burn categories are once again probably simply a matter of taste rather than any strategic difference.  Where Tarmotog took risks with his manabase, I take risks with the Dwarven twins.  We both have versatile anti-artifact card (Duergar Hedge-Mage vs Hearth Kami and Smash to Smithereens).  Where I have no x-spells, Tarmotog has three.  On the individual card level, I prefer Thunderbolt to Lava Spike since I feel Thunderbolt's alternative use justifies the extra mana; I also specifically avoided Seal of Fire and Tarfire, since they can enhance an opposing Tarmogoyf, and there are alternatives like Rift Bolt.  I would also like to point out another pet card of mine, Lightning Storm.  It can be a useful outlet in late games for extra lands, and can give you unexpected wins with your opponent feeling safe sitting at five life with an empty board.

Two hundred cards later, what have we learned?  While one might think mono-red decks are all the same, there is a large amount of room for diversity and individual expression.  You can load your deck with more one-drops if you want a quick start to beat counterspells, or you can include ten mana disruption spells if you think that will win the game.  If you're worried about green decks, you can try for haste or equipment.  Whatever deck you choose to play, I hope these tables provide a useful and quick reference when you're deck building.

Addendum

Between the time I wrote this article and publication, I played in the weekend Premiere Event.  I will highlight some of my card choices, and how they impacted that event.

Round 1: X_TREME with UR control

Game 1: When X_TREME played a Vivid land to start, I would have fist pumped if it wouldn't have looked awkward sitting alone in a room.  I played first and second turn Stream Hopper and Frenzied Goblin.  These creatures combined for nine damage before being hit by an Electrolyze, as they were able to get by blockers.  Stream Hopper in isolation is not a great card, but it fills the useful role of one-drop with some evasion.  With so many singleton decks taking a few turns to assemble a multicolor manabase, it is easy for a one-drop to do 3-4 damage.  Those two creatures were the only ones I played, and I finished the game out with burn through counterspells.

Game 2: I was stuck on two lands, but had Orcish Librarian.  This allowed me to hit my third land drop, and the game became academic at that point.

Round 2: Th00mor with MonoR

I know Th00mor best for his free spell Chronatog Vanguard decks that he pioneered.  This mirror match illustrates how some of the card choices I made can influence matches. Game 1, I am again stuck on two lands until turn 6, and Th00mor runs me over.

Game 2: This game was fairly uninteresting except for one series of plays.  He played Duergar Hedge-Mage into an empty board, which was just a useless Gray Ogre.  I eventually won the game on the back of a Sword of Ice and Fire.  Had his Hedge-Mage been a Hearth Kami, or he had been more patient, he may have been able to come back.

Game 3: Th00mor was on the play, but had no one drop, and his first play was Ankh of Mishra.  I dislike both Ankh of Mishra and Zo-Zu, the Punisher.  Both cards have the ability to deal 8-10 damage, but have significant downsides in their opportunity costs. By playing Ankh on turn two, Th00mor could not play a creature, and had no pressure on the board.  Yet, every turn he waited to play the Ankh, he lost out on two damage.  Furthermore, since we are both playing MonoR, the Ankh nets him no advantage, since he is dealing damage to himself.  Similarly for Zo-Zu, one could instead play Ram-Gang or Inner-Flame Acolyte and deal 3-4 damage immediately, instead of waiting a few turns for the damage, and also doing damage one's self.

After the Ankh, the game continued in typical monoR mirror match fashion, with each of us spending removal to kill creatures, until I draw two mirror match All-Stars: Giant Solifuge and Ashenmoor Liege.  Giant Solifuge is great since he can't spend a burn spell to kill it.  Ashenmoor Liege guarantees that even when it dies, it does damage.  This game also illustrates how conditional Cursed Scroll is, since he was only able to activate it once (four mana for two damage is terrible), and was not able to play lands to empty his hand due to Ankh of Mishra.

Round 3: Lundstrom with UG Tempo

Game 1: Red decks never like to see green, and I got blown out this match.  In game 1, I missed my one-drop, and played too cautiously around counterspells, and lost the game while he was at 18 life and had two 4/4s.  While the deck can usually handle one 4/4, each additional creature requires more luck to overcome.

Game 2: I again missed my one-drop, but had a Dwarven Miner to keep him off his mana.  Unfortunately, he had a Llanowar Elves to keep going.  The key play was probably turn five.  I had four mana, with Spitting Earth, Grim Lavamancer, and Stalking Yeti in hand, while he was tapped out.  I played Stalking Yeti, which got hit with Force of Will.  He untapped and played Man-o'-War, Phantom Centaur, and Grizzly Fate on the next three turns, while I used Spitting Earth on a Mire Boa.  In retrospect, I probably should have killed the Elves with Spitting Earth on turn 5, and played Grim Lavamancer as backup.  He still would have drawn enough lands to put me in trouble, but I may have had a better chance.

Round 4: Chrunch with MonoR

Game 1: He got stuck on two lands, and I exacerbated the problem with Pillage.

Game 2: We both trade spells and creatures early until he landed a Giant Solifuge, and was able to clear the way for it with burn.  There was an interesting moment early in the game when he had a morp vs my 2/2.  I could have removed the morph with Sudden Shock, but was worried about Gathan Raiders.  Alternatively, I could have Flame Javelined the morph, but that felt like overkill.  In the end, we traded 2/2s, the morph was a Dwarven Blastminer, and I was overthinking things.  It's probably best not to play around individual cards in singleton.

Game 3: On the play, I kept an ok hand with a few two drops.  He lead with a Jackal Pup, and then on turn 2 played Figure of Destiny and Boros Garrison.  In return I played a Dwarven Blastminer face down.  He elected not to kill it, and on my turn, I flipped the miner over and blew up his Garrison.  I just spent seven mana to destroy a land, believe it was the right play, and feel dirty.  The rest of the game, he was never able to get more than two mana, and I closed it out easily.  This is a great example of how swingy the Dwarven twins can be. If he had removed it, or played a different land, the game could have gone much differently.

Round 5: Gainsay with UWB control

Game 1: Sun Droplet, gg.

Game 2: No Sun Droplet, gg.

Game 3: I was not impressed by his deck until game 3.  His deck had some tutoring, and life-gain, but I had not seen any clear win conditions in it.  In this game, I kept a 6-land hand where two of the lands were Wasteland and Mutavault, figuring those aren't really lands.  We traded spells until he was at ten life with a Magus of the Tabernacle to my 2/2, Mutavault, and Mishra's Factory.  I attacked him to 6, then played Firebolt to get him to 4.  I had plenty of lands for a flashback Firebolt to finish the game.  Then he started recovering, remanding a Giant Solifuge, then putting Faith's Fetters on Mutavault to recover to 8.  To tax me more, he played Pendrell Mists.  Just as I was recovering, I finally saw his whole deck came together as he played Epicenter, and I could no longer pay my tax.  He was at 4, and I had Sudden Shock, so I waited to see if I could resolve the last few points of damage, but a Zuran Orb and Armageddon stopped those dreams.

After this round, eliminated from the Top Eight, I quit the tournament for other engagements.  I am not sure I would play a red deck in the future.  While I thought my deck should be able to beat multicolor control decks, it only went 3-3 in games.  Furthermore, you will inevitably play a few mirror matches in which it is hard to gain an advantage, even with careful deck construction.  While I wouldn't advocate playing a three color deck, there may be enough mana fixing in the format for a good two-color midrange deck to thrive.