Games

Some good games I recommend are Alto's Adventure / Odyssey, any bejeweled game, Cell to Singularity, Idle Slayer, Monument Valley, Reigns, Sky Force Reloaded, and Stick Fight Shadow Warrior. Hopefully that's enough!

I used to play Unblock Me. Made it maybe 1000 levels in various difficulties before stopping.

Assuming that you have Netflix, open it, scroll to games and open the section. There are tons of great games without any microtransactions or ads. They're overwhelmingly commercial games licensed by Netflix.

I have lately been enjoying Legends if runeterra's Path of champions mode (PvE)

I'm enjoying isle of arrows right now. Tower defense but instead of having a set map and same towers you get to draw cards and have to make do with what you get. Some cards give you pathing for the mobs, other expand the buildable area, others give you towers. Simple and fun. Game pauses between waves so you can take as long as you want to prepare.

If you have a Netflix account, you can get Bloons TD6 for free on Android. It's fun and the microtransactions are completely unnecessary and hidden away. Beware it's a battery hog though

Also, if you like puzzles, look up the various variant sudoku apps from Studio Goya, particularly the one called "Cracking the Cryptic"

Grim Quest and Grim Tides. Two games by the same person. I haven't played Grim tides yet, but it's also free. Grim Quest is not a particularly large game, but I've still managed to play it over many years. I did a full run of each difficulty one by one. There is a bit to learn before it feels easy and casual, but it does get there. To be fair, I try to play it without dying. If I let myself die, it would be alot more casual even from the start. Dying is not heavily penalized on default settings, but you can alternately choose to play hardcore. Otherwise dying usually just means you gained less money for that run, and didn't make the game any harder. The game only gets harder when you successfully clear a dungeon. You can also just exit the unfinished dungeon without dying and keep most of what you have acquired so far on that run, minus a small fee for quitting the dungeon.

There are preset difficulty options, but you can also craft your own custom difficulty. There are things you could spend money on, I think it may have started out with ads. But I consider games with ads that you can pay to get rid of as basically a free demo, and getting rid of ads is the purchase price if you like the game. So they don't deter me if they don't basically break the game to add ads to it, or affect the flow of the game whether the ads are there or not.

Galaxy Genome, it's a space exploration game. Sort of a project to make a comprehensive 2D version of Elite: Dangerous. Or at least it started as that, I don't know if it has achieved and surpassed that by now. It was pretty far along last I played. And that was a while ago now. I kind of play games on and off for years, so that is mostly gonna be a running theme of all the games I post here. Games that you find yourself wanting to pick back up again, over and over.

bloons td6 is a nice cozy game, one of my faves

Exiled Kingdoms, its an older isometric 2D adventure RPG. Kinda feels like it would have been made 30 years ago for pc, but it was made relatively recently for phones. I don't think there was any micro transactions. It may have had an initial purchase price, not sure. That's usually what I look for in a phone game. The traditional model of buying a game and then just playing a game. No gross mobile game stuff.

Hmm, I was gonna say moonshades, last time I played it there wasn't much for things you could buy. But when I look now, there is. So I can't say for sure how unnecessary any of it would feel now, but it wasn't necessary back when I played last. It's kind of like the old early 3D party dungeon/maze crawlers where you use the arrow keys to walk one "block" at a time. There is only 2 party members in this. So you still sort of get the group synergy stuff, but each character is a bigger share of the team power. You could do a tank/healer thing or magic damage/melee damage, or not have either one focus on anything in particular.

I hope it's still not necessary to buy anything, it was a good game. But the store is pretty comprehensive now, so that has me worried.

If you don't mind a classic chess. Blitz/bullet/rapid/horde are different styles that don't take as long to learn enough to have fun. Chess puzzles or against the computer are available if you want to keep it strictly single player. Lichess for multiplayer or I like chess tactics pro for puzzles.

Crosswords, there are programs like alphacross that aggregate from other sources to try different puzzles to find ones that aren't too easy or hard.

Soko++

Loop hero is really fun imo! Also solitarica

I really like Usagi Shima. There is not much gameplay, but it's a nice game to just relax for a few minutes. Also "Really Bad Chess" is a nice twist on chess. :D

Not sure what sort of length on play you're looking for but wingspan and terraforming Mars are both really good board games that have good-to-quite-good mobile versions.

Friends and dragons. It's a bit like easy chess with d&d style classes and species. It has transactions, but you can easily do well for free. I've been free playing for years (though I did throw them $10 around year 2 because of how much entertainment I got from it)

Cell to Singularity is a great little mobile game that does have microtransactions but are easy to ignore/avoid. I played through it several times and may need to dust it off for another playthrough. Great music too.

Royal Match and Royal Kingdom are both add free and free to play. You can buy stuff, but you dont need to

First one coming to mind for me is Pillar Hop. Very simple, chill, and just had ads iirc (I block them, but I'm pretty sure it does, anyway.)

Mini Motor Racing might be a good match. It has some DLC available (additional cars), but none of it is necessary to enjoy the game.