Favorite gacha game/app?

So playing gacha games became quite the trend latly, and even some companies started releasing gacha-type of games for their growing popularity. Among them, there's Genshin Impact, which is one of the most popular gacha game as for today!

I'm F2P, but I grew a big love for gacha-type of games, and play Genshin, even Cookie Run, all sort of Anime-like gacha type of apps and more.

What is your favorite gacha game and why do you like it? Let me know!

I have an android, if that.
I love minimalist games, preferably with a retro or flat design, without any flashing banners, notifications at 3 a.m. and without much donation. Basically all kinds of logic and puzzles. Tetrises, analogues of 2048, pipelines, labyrinths ...
A list of those that stayed with me longer than 2-3 months:

Make7!
I love hue (I stick for hours)
Make me 10
Reigns (paid)
Block puzzle (almost tetris)
Lazors (pass a laser beam through different materials)
Two eyes (Japanese crosswords)
Topsoil
Euclidea (cool app for geometry lovers, but unfortunately I'm a bit dumb for it)
Little alchemy 2