Ok, got my PS1 games sitting out for a change so more obscure goodness on that system.
Treasures of the deep
Tail Concerto (Sounds like a furry porn huh?)
The entire Jumping Flash! series (all 2 of them that I know of..)
Megaman Legends (Both were good in different ways though)
Legend of Mana
The Point Blank series
I can still probably find a few more titles from other systems too...
Megarace 2 [ PC ] => A time piece do to its jaw-dropping prerendered 3D race venues and weird sense of humor via Lance Boyle.
Endorfun [ PC ] => Another unique puzzle creation from Denmark and looks best in 256 color mode. Also one of the most challenging games of its genre to date.
Vivesector [ PC ] => Straight out of Russia itself and sold exclusively in European market. This FPS monster is Doctor Monraeu gone Frankenstein.
Psychonauts...well... before Yahtzee reviewed it and every bugger went and bought it.
Mashed: this fell into the Categorical misprint of missing out an online feature and thus rendered the game very unpopular as it was almost specifically designed for that purpose. Oh well it was only Â£3.
Screamer: The old DOS racer and to this day remains one of my top racing games simply for the awesome arcade element very similar to that of Daytona, except less crap in some instances. I.e. Not all the tracks go round in a circle.
Descent: A trilogy which died a miserable death at the hands of megacorporations with lots of money. A bi achievement at the time, but unfortunately the competition overlaped the hell out of it and it kinda got forgotten about. The first one still remains a technological breakthrough and ceases to amaze me for what it did. The series ended at the third, hence trilogy, but with advertising campaings like this http://www.youtube.com/watch?v=5RUakcYEkew what do you expect?
"Terranigma", had to play this one as a ROM on emulator since it was only released in europe. Small town boy living in a town on the INSIDE of the hollow earth, he resurfaces to discover that the surface of the planet has been decimated, and it's up to him to restore it back.