The Playstation Portable is one of the platforms I get the most guide requests for. We also have the PSP as our "Console of the Month" in our planning for this coming Fall.
I'm hoping to collaborate with the community on both a Defining Games guide and a Beginner's Guide to publish before then, but I really need help on these as it's possibly one of the platforms I know the least about -- despite it being rather popular and recent. (Although the recent aspect is a major handicap for me)
Anyway....
To start, let's nominate some heavy hitters (we can group series together too) and some honorable mentions.
The goal isn't necessarily only cover the most popular games, but the ones that really were important parts of the handhelds history and made the biggest cultural impact.
I'd probably shoot for around 12 primary games/series as that puts it in the same number as platforms like the Sega Master System, Dreamcast, and the original Xbox.
If you need to see those examples, here's the links
https://www.racketboy.com/retro/games-t ... osoft-xbox
https://www.racketboy.com/retro/games-t ... ter-system
https://www.racketboy.com/retro/games-t ... -dreamcast (Dreamcast is one of the first ones I ever did and it needs an overhaul for quality improvement)
For reference, here's the GBA one too -- but it has a larger library and was worthy of a lengthier guide
https://www.racketboy.com/retro/the-gam ... oy-advance
If you want to help write fuller/partial entries for any of the games or series, please speak up as well. We can use all the help we can get

Thanks!