I have been lamenting the loss of the pure rock cocaine that was Hunger Quest. If anyone has anyway to bootleg it, I will gladly bury whatever you want in a shallow, unmarked place for that. It was free on Android with some cash perks, no ads, and a lot of fun.
The "Hey! That's My Fish!" app (I can only speak for Android) is outstanding, good for zero(!) to four players, and is worth the incredibly humble price many, many times over. It's $2 in the states, which is just nuts for a game of this quality.
I've been playing the fine and dorky time waster "Knights of Pen and Paper," which is "Actually Free" from the Amazon App Store if you have Prime. This means the normal kick-in cash for loot is free, as you have the ability to "buy" in-game currency for free. This kind of ruins a lot of games on Amazon Prime because they were designed with a cash-for-easy-mode infrastructure. I totally abused this by accident in KoP&P, and broke the difficulty curve, but I still have had a couple of challenging fights. Whatever, it's good enough, and you can either play all day or while waiting for an elevator.
If you have enough storage memory for Galaxy on Fire 2, it's pretty amazing. It's a shooty ships in space dogfighter, with some trading elements and RPG elements. It's 3d, you can pilot by tilting your phone. It's like Endless Sky only with fun dogfighting, or like No Man's Sky only with fun dogfighting (and no planet exploration, survival, or zoology).