i'll bite. This is by no means an exhaustive list, but from my experience collecting for these systems, some of these are very, very rare.
PS1
- City of Lost Children
- Silent Bomber
- Tail Concerto
- The Misadventures of Tron Bonne
- Easter Bunny's Big Day
- Revelations: Persona
- Fox Hunt
- Clock Tower II: The Struggle Within
- Dragon Ball GT: Final Bout (1997 Bandai release)
- Erghiez
- Elemental Gearbolt
- In the Hunt (especially jewel case version)
- Killing Zone
- Monkey Magic
- Shadow Tower
- Tall Infinity
Dreamcast
- Cannon Spike
- Dragon Riders
- Giga Wing 2
- IllBleed
- Project Justice
- Shenmue Limited Edition
- Sonic Adventure Limited Edition