Doesn't have to be a top ten. Could be a top anything(3, 5, whatever you want). It can be from any time period on any video game console. The only rule is that the game can't be popular. No(For example) Halo 3, Metal Gear Solid 4, Grand Theft Auto IV, Fallout 3, Bioshock or Legend of Zelda's.It has to be something unknown, even if only slightly unknown.
My list:
1) RealMyst - An adventure game for the PC. Developed by Cyan.
2) No More Heroes - A hack-n'-slash action game for the Nintendo Wii. Developed by Suda 51.
3) Seven Kingdoms: Ancient Adversaries - An RTS for the PC. Developed by Enlight Software.
4) Dink Smallwood - A freeware(search on Google for a free download) action RPG for the PC. I have no idea who developed it.
5) Moon - A FPS for the Nintendo DS. Developed by Renegade Kid.
Now it's your turn.

Well, popular is rather opinionated, don't you think?
1. Poxnora. Shh.
2. The Ship.

holy crap someone else plays poxnora? i'm on a little hiatus for the last two months, i got burned out but i've been playing it for about 2 years now.
currently my comp has some major mouse issues that are preventing me from playing it (some reason my left click functions as my right click and right click doesn't work, i've tried multiple mice, different usb ports, uninstalling drivers, malware scans, control panel mouse settings, nothing fixes it, its freaking bizarre and really really annoying), but i plan on jumping back in soon. i use the same name as here.

Lol, I use to play Poxnora. Got kinda bored of the game but that was a long time ago, I might check it out again sometime.

Fighter Destiny 2 for the N64.
Total Annihilation Kingdoms for the PC.
Each of those count as 5 games.

In no particular order:
1. Sanitarium (PC)
2. Giants: Citizen Kabuto (PC)
3. Sacrifice (PC)
4. Wizball (C64)
5. Deuteros: The Next Millennium (Amiga)

All PC games:
1. King's Bounty: The Legend (best turn based srpg ever)
2. Fantasy Wars (great tbs)
3. Arcanum (love the scenario)
4. Temple of Elemental Evil (fantastic gameplay)
5. Psychonauts (pure love)
6. Clive Barker's Jericho (soooo underrated)
7. Divine Divinity (it's magic)
8. Nox (while not great, it's a very good game)

Here is 5 to start with.
Tribes 2
Cultures Series
Machines 3D
Nations
Industry Giant II
Also MrEco if you are interested in Myst games let me know I will make you a great deal for I think every Myst game made.

Rocket Knight Adventure
Easily one of the best games on the Genesis and no one has ever heard of it...except the HVGN.

Alien Breed certainly was very popular at the time.

1. Crusader: No Remorse
2. Ecco the Dolphin
3. HeXen
4. Kirby's Adventure
5. Shadowgate

Argh! How could I forget?!? Yes, definitely Crusader: No Remorse, and also the sequel, Crusader: No Regret. Both are exceptionally underrated games!

Plug time!
Check out my Crusader website, Echo Sector.

Hehe, no need to plug at me. I have checked it out. Several times ;-)