Sorry to bump what might be a necro-thread, I don't know how things work on these forums. But I'd like to add a few titles of my own, if this discussion is still of use to anyone. It was to me, as I'm a collector of obscure PS1 games and review them on YouTube (as JohnGreasyGamer).
Tombi!/Tomba! - this is one of those games a lot of you have heard about, but unless you're in the US this game isn't easily obtainable. Be it due to its quantity (didn't sell many copies and isn't in Platinum therefore it's now rare) or its price (over £200 in some cases), this is one tough cookie to get. Tombi! follows the story of the title character attempting to defeat the Seven Evil Pigs, who have stolen his grandfather's bracelet. It's a nice little game that's 20 or so hours long giving some great platforming and interesting RPG mechanics. You can catch my review on it here: http://www.youtube.com/watch?v=QjiN_k3A7UY
Kula World - This game is very obscure in so many ways. It's very similar to the recent physics game Marble Blast Ultra, where players take control of a volley ball and rotate the world to their liking to reach the end of the stage. Kula World is more of an adventure/puzzle game than it is a platform game, but does allow for some great score attack and requires some thinking. Fun for the kids!
Ghost in the Shell - this game is based off the hit Manga of the same name, which spawned dozens of movies, TV shows and even the PS2 game which isn't all that rare. The game also inspired Oni greatly, and I'm sure we've all seen that on store shelves for under a dollar. Or a pound, at least. Ghost in the Shell is a great Third-Person Shooter which I hope to review at some point, and really gives the genre a good name! Great soundtrack and amazing gameplay, making it a superb obscure title!
Assault / Assault: Retribution - this game is a run 'n' gun platformer in the same vein as Contra. Aliens come on screen, you blast 'em and kill 'em dead! That's how a video game should be made. But Assault fills the screen with explosions, a great soundtrack, amazing control, huge replayability and if there's co-op you can be sure as Hell it'll be **bleep** fun!
Clock Tower - I've not actually played this game but I've heard it's remeniscent of Silent Hill. It's a survival horror game in which a serial killer chases after the player, and you as the unlikely hero must find out the truth. I've heard good things about it and with its price range being so freakin' high, I can actually believe it's worth the money.
I'm not here to promote my channel, that's not the point. I'm just trying to help collectors like myself find the weird and wonderful, and this thread helped me find a few purchases.
Thanks for taking the time to read this!