Minecraft, of course. I've enjoyed the Civcraft series of servers that simulate nation-building very well, in Survival mode with other players a danger. CivMC.net is the most popular current iteration.
Haven and Hearth is a non-Minecraft MMORPG along the same lines, similar to early Ultima Online in aesthetic but with inheritance instead of resurrection.
I got Slay the Spire on my tablet, spending $10 of those Google Rewards I've been saving up. I missed when that first came out, due to playing CivCraft :) Have been doing the daily runs, daily!
Shattered Pixel Dungeon was more last year, but I have played a bit of the update this year. It is very inspiring to have an open source Android+PC game that's a lot of fun with a great community, with people actually using the source to make their own variants on both platforms.
Picked up Mushroom Musume from itch.io, a nice almost-rogue-like adventure / story / creature-raising game . Definitely worth a few bucks but free if you can't.
Hexonia is a polished single-player mini Civilization-style game that at first glance seems gratuitously monetized, but any ads and purchases are voluntary; unlocking things without paying is it's own strategy game. The scope is limited, but I've really enjoyed the challenges and have gotten way more than my money's worth ($0).
Bought Phantom Brave on Steam sale, the story is cute but maybe too simplistic; good voice acting though. The turn-based combat on the missions is fun, I really do like an alternative to the grid.
Tactics Ogre Reborn on the same Steam sale, "good but not the greatest of all time" is how I'd describe it so far. Out of the two I've spent a lot more time on Phantom Brave and care about Tactics Ogre characters far less.
The letters I and C?