My all-time favorite has to be Skeletons. I think it's really fun to play a theme where the creatures never die, just keep coming back over and over and over.

[[Gutterbones]], [[Sanitarium Skeleton]], and [[Reassembling Skeleton]] are my favorites. You can add other great sacrifice effect cards like [[Bone Splinters]] or [[Village Rites]] and [[Altar's Reap]].

I like my big cool creatures, so I love my Dinosaur, Dragon, Sea Monster, Sliver, and Angel decks. I've actually made two Dinosaur and Dragon decks each, one in paper for Commander and one on Arena.

[[Gishath, Sun's Avatar]] is a super cool commander. Some of my favorite cards in the deck are the new dinos from March of the Machine: [[Ghalta and Mavren]] and [[Etali, Primal Conqueror]]. Ghalta and Mavren is a really fun card for the flavor, and Etali is ridiculously strong.

Some of my favorite Dragons are [[Klauth, Unrivaled Ancient]] who generates a ton of mana to cast more Dragons with, and [[Miirym, Sentinel Wyrm]] who gives you twice the Dragon per Dragon. Copying [[Niv-Mizzet, Parun]] creates a really strong effect that opponents always have a tough time figuring out how to handle, and copying [[Wrathful Red Dragon]] means that anyone swinging into your board is likely to just die from the retribution damage. I also opened a copy of [[Terror of the Peaks]] in a random sample pack from a draft that's still one of my best-ever pulls, and that thing puts in tons of work.

Slivers we’re one of my personal favorites. It just feels so cool to build out a swarm in whichever color mix you feel like and to be able to get fun and flavorful results. Sliver Queen was just awesome.

I think it depends on whether or not you are building a standard vs commander deck. Since commander decks are larger it can get more complicated trying to build a full theme deck with some of the more obscure creature types. That being said you can't go wrong with a cat deck.

Agreed, themes of all kinds can be fun! And I'm loving everyone's themes here. Most of my decks have a theme, though sometimes I sacrifice it for a little performance.

My three current favorites:

• Unionize : colorless, Assembly Worker tribal (took me a while to get that to work right! In particular [[Foundry Inspector]] + [[Self Assembler]] is fun)
• Red Wedding : black/red, vampire tribal with [[Edgar, Charmed Groom]] and [[Olivia, Crimson Bride]] (with almost all wedding themed cards)
• Ballroom Blitz : black/red, blitz ability aggro with graveyard return... basically "dancing" the cards between hand, graveyard, and battlefield (not the most efficient but pretty fun and efficient!)

I love token decks of all types. Squirrel tokens, copy tokens, whatever. My favorite is a mono-white deck that does nothing but create tokens and accrue value from them. I don’t usually like to attack with my tokens, so I generally wait until I can end the game with something like [[Starlight Spectacular]] or just dig for [[Halo Fountain]].

I love seeing an artifact deck build up a board state, and then just activate a bunch of abilities on someone's end step.

Also playing with something that changes the way the game functions like using a [[Leylines of Singularly]] to shut down tokens, forcing a game to close out with a [[forced fruition]], or equipping an opponent's creature with [[spy kit]] and hitting it with [[eradicate]] to exile their non legendary creatures from all zones.