PSP fighting games mostly.
I had a PS2 back in the day but never understood the overwhelming boner everyone had for it. The Gamecube loaded most multi platform games so much faster. I know like the PS1, the PS2 had a wealth of RPGs, but I'm guessing there are a lot of people who are into those games that never actually finished or played half of what they bought. A lot of the first party titles have already been remastered and I'm guessing the more obscure shit won't be on the PS4. I would like to see Sony get REZ at some point though.