Well...if you jaibreak, you could pirate...but free iOS games tend to be crap.
The only freebie games I play is Clash of Clans and Osu!Stream (both filled with IAP).
But if you had money, I'd recommend:
- Bastion
- Limbo
- TWEWY:Solo Remix
- Ace Attorney remakes
You could also launch some emulators when rooted, but don't expect anything amazing.