A lot of really good older games have been ported to mobile and work fantastically. Knights of the Old Republic, Neverwinter Nights, and Baldur’s Gate just to name a few. Hell, you can play Baldur’s Gate multiplayer, cross-platform with PC players even! There’s also fo2.exe on the Play Store, which lets you play Fallout 1 & 2 on mobile provided you have access to the files from the PC versions. Oh, and Doom ports galore, of course.
As far as mobile-only or mobile-specific games, my favorite is probably Caves, a surprisingly well done and completely free roguelike.
Slay the Spire is excellent on mobile, it’s a roguelike deck builder.
Might not be the answer you expect, but I have an iPhone and I got myself an Apple Arcade subscription without expecting much (I didn’t play mobile games at all before that, because they tend to feel either unoriginal, or scammy, or both), and I was surprised at how most games (not all games, but still) were truly original, and none of them were scammy since I was technically paying for them with the subscription. It’s been a surprisingly nice exploration.
RCT classic is pretty good. Not as good as OpenRCT but still quite good.
Slay The Spire is also very good, though the mobile version is a bit bigger than the PC game
Definitely the mobile version of Stardew Valley
Cytus II, it’s a great rhythm game with a cool storyline
May be the commercial one but actually Candy crush is a nice one
I work at a gaming company - Candy crush is known for employing the same tactics that keep people sitting at slot machines for 8 hours a day, and every damn PM wants to copy those patterns.
