The good thing having Android is you can play Playstation 1 (PSX) games. So far, I can only list the two best Android psx emulator.
Psx4droid v2 is a Sony Playstation 1 emulator for high-end Androids (600MHz+ recommended). This emulator is the first and the pioneer psx emulator for Android.
This is the best psx emulator for Android. The creator also made psx emulator for PC. So, it can be guaranteed as a high quality emulator. A lot of games are supported and played smoothly using this emulator.