If you do your research, though, you’ll find a treasure trove of easily-accessible gems — like a solo dev’s reworked Diablo village where you watch your party auto-battle its way through catacombs, or an idle game where managing catnip supply chains spirals into deep-space civilization management. Deduction mysteries, language-learning puzzles, and dungeon crawlers usually come with a price tag and a download bar.

Tragically for your productivity and spare time, these ten do not.