Shame there is not just one thread to stick interesting Indie games on that might bring them to GoG's attention, so i've resurrected one of the better/more comprehensive threads.
Another shout for Osmos, a very polished and relaxing game to play.
Waking Mars - a sci-fi themed puzzle adventure, again very polished.
Do you mean as a recommendation for GOG members or as a wish to add them to GOG's catalogue? Because Waking Mars is part of GOG's catalogue
already, just in case you overlooked it. :) (And I agree, it's one of my favorite indie games!)