The ageing Samsung Galaxy S II still has plenty of life in it. It runs Minecraft PE and Terraria perfectly well!
It might be old, but there are still developers hacking at it and releasing firmware upgrades with modern versions of Android. I decided to try this unofficial build of Slimkat i9100 Sabermod. My previous install barfed and half the apps on it disappeared somehow!
Sabermod installed easily. I already had TWRP installed so it was only a matter of installing the various zip files through it. Give it a go if you have this old phone, especially if you’ve never messed around with ROMs and have this phone lying around. The usual caveats apply. YMMV and you might soft-brick your phone.