I don’t know that particular system, so I can’t give any hardware-specific suggestions. However, it might be worth checking out the games that previously were included in Humble Mobile Bundles, especially the very first ones. Sorry, I don’t have a nice to browse list, but this site seems usable enough: barter.vg/bundles/3/76/

That said, OpenTTD is available on F-Droid. That should keep you busy for a while 😉