Devs who help you keep a game for if Desura goes down.

Alcarys Complex
Alternative: Itch.io
Steam: The game has been Greenlit, but the game isn't on Steam yet.
How: "If you bought AC either here or got it in the Indie Royale bundle, e-mail help at modestarcade dot com with your Desura username and I'll give you a key you can use over on"

Porradaria Upgrade + Porradaria 2
Alternative: Itch.io
Steam: No, Porradaria was never approved on Steam Greenlight. So I can't provide Steam Keys until it is green lit
How: "When requesting, don't let your profile private, so I can confirm you really own the game. If you bought it from a bundle (i.e.: Indie Gala, Bundle Badits, etc) you just have to inform the name of the bundle you bought it. Please request it quickly, if Desura ceases to exist, I won't be able to confirm anything and send you the keys."

I think alot of this news will become scattered and one can't be expected to check every single game they own, so if you know of such a game and dev post a link and a way to contact them or getting another key post it here and i will add it to the op.