Pretty much games that I can't find anywhere else.

Not to be rude, but couldn't you have looked up a list?

Pingu is a Steam undercover agent.

I think there are some that other distributors just haven't cared enough to try to go after, or only GOG has really shown interest in because of their original focus on old games. I believe King of Dragon Pass is being sold here (aside from iOS) exclusively because GOG helped bring the original into the modern age.

Hm, I think Signal Ops may be the only one? Although it has been Greenlit now, so it'll be on Steam at some point...

Most older games have some sort of physical release and most newer games can be found on other services as well.

I was thinking of digital distribution exclusively. GOG has many EA classics that I don't think even Origin does (although I could be wrong), and I assume various other older games that other services haven't bothered to go after.

Signal Ops is on Desura too.

I love this. Second post and we're already at conspiracy theory :)

You ... you're an undercover agent too.

edit - realized my post was wrong. don't really have anything else to say.

Interesting...on their website they only mention Gog.

dont mind me, misunderstood the OP

Teenagent, maybe?

I believe you can only buy VR Soccer 96 here on GOG

Nope :p - http://www.desura.com/games/teenagent

...I'm just going to stare at this post with a deranged grin, wondering what it said. :P