Monster Hunter Freedom Unite
Ys Seven
Dungeon Maker
Dungeon Siege
Phantasy Star Portable
Lord of Arcana
Untold Legends
Xmen Legends
Diablo 1 PSX

Idk what a PSP is
But you should just ask Doug he loves rpg's
You should also join PlayStation

I honestly don't know many ARPG's when it comes to PSP xD

the only 1s I can name that aren't on his list are Ys: Oath in Felghana and Monster Hunter Portable 3rd (although it was never localized)

there is a english patched one
but its really nothing compared to unite

unite is basically a harder more content rich verison of the 3rd

no Unite is the better version of 2nd aka the G version of Portable 2nd (or Freedom 2 as it was known here), P3rd is just the 3rd gen PSP game
and I was slightly hinting with my portable 3rd mention :P, I played it a lot on my PSP and eventually bought the HD ver for PS3

Final fantasy VII psx