We recently covered the fastest formats of the Arena era, but what about the opposite end of the scale? Which formats let you spin your wheels and take your sweet time?

Just a quick reminder, though. The methodology here (comparing the mean number of turns) is not perfect. More importantly, the gap between the fastest format and the slowest is a mere 1.5 turns (1.49, in fact). Basically, slow formats aren't that slow nowadays.

3. Theros Beyond Death

Mean Turns 9.807

When I think of THB, I think of absurd, but expensive, bomb rares. Dream Trawler is the poster child for "you're already dead" game play, but six mana is a lot, and that mana cost is not always going to be available, even if you do have six lands in play. Kiora Bests the Sea God is a little easier on the mana symbols, but costs a whopping seven and still takes three turns to truly pop-off. Even Ashiok, Nightmare Muse - one of the best Limited rares of all time - takes a while to get games over with.

But there's a lot more to a limited format that its rares. Most of the best commons and uncommons in this set were Blue and Black. Cards like Elspeth's Nightmare were great at accruing small bits of value while also dealing with your opponent's board. Mire Triton was a hell of a road block, as was Alirios Enraptured. There's a lot of removal at the top of the 17lands rankings, and not a lot of red or White cards. For every Anax, Hardened in the Forge, there's a Drag to the Underworld waiting to get rid of it. Control, and to some extent, tempo, was king in THB so it's no surprise to see it on this list.

2. Guilds of Ravnica

Mean Turns 9.899

Duel Decks are long gone, but this set would have made a good case for Boros vs Dimir. What is fascinating here is that the best cards in the set were mostly uncommons, with a few exceptions for obvious bombs like Niv-Mizzet, Parun and Connive // Concoct. Nightveil Predator topped the pile - the best entry in a powerful cycle that also included another one of the best cards in the set, Truefire Captain. There are almost no Green cards in the top echelons of 17lands data, which says a lot about the plight of midrange decks in GRN.

With Boros being so powerful (the best two-color deck in the format), it's hard to understand how the format could end up being the second-slowest since Arena began. Dimir being the second-best guild honestly makes things more confusing. How could two polar opposite decks both be at the top of the food chain? Well, a lot of the best Boros cards were about going wide and creating inevitability rather than smashing face as quickly as possible. Boros Challenger was a solid attacker, but it wasn't unreasonable to get to game states where you activated its ability twice to end the game. Mentor as an ability required you to attack with multiple creatures. That wasn't always easy, so you would often be waiting to draw a removal spell like Lava Coil in order to get through.

1. Ravnica Allegiance

Mean Turns 9.924

A rare format where Orzhov was the best guild. Yeah, Ethereal Absolution helped, but Black-White players had an embarrassment of riches when it came to dragging the game out. The Wrath in the set, Kaya's Wrath, even gained life, in case clearing the board wasn't enough of a speed bump.

Few decks were even trying to be aggressive in this set, though. Rakdos was an attrition-focused sacrifice deck and while the other red deck, Gruul, could be fast, the best thing to do with the Riot mechanic was almost always to make your Zhur-Taa Goblin a 3/3.

Azorius was statistically the worst guild in the set, but it had a lot of good cards and most of them slowed the game down. Clear the Mind is infamous for being a one-card win condition at common, but it often ended up being a bit too slow. The best Blue deck in the format was actually Simic, but it, too, was about building to an unassailable late game. Ideally, you were looking for something like Mass Manipulation or Hydroid Krasis to finish things off.

Surprisingly, none of the multi-colored gates decks were especially strong. The best three-color deck was Temur, which couldn't play Archway Angel to slow games but did make excellent use of Gatebreaker Ram. Four and five-colour decks don't really have enough data to draw conclusions, but that in itself tells you all you need to know about their viability.

This was a set designed, deliberately, to be slow. And it was. It really was.