Well i am Indie Fan for sure, i only play indies ^^
I can list some good ones and explain them for others:
A Nation of Wind -I loved that one, you are sky ship and build civilization on sky islands while defending them from monsters, EPIC!
FREE Naev - Best open world space rpg i played, but the fight system is a bit hard.
FREE Hacknet - Well obvoisly you are hacker and hack, it is like simplistic version of uplink, but fun in pvp.
FREE Savage 2 - Good RTS Game where your soldiers are players.
Ace of Spades - Funny blocky FPS where everything could be destroyed, like minecraft with guns.
FREE Creeper World 1/2 - One of best games i played, hard to explain, you defend yourself from the creeper, small viruses which toghether look like fluid, and they mean to kill you. In 1 epic is that you build civilization on islands higher than the sea of creeper (View from up) And in 2 its more strategic base building (platformy View)
Driftmoon - Still in development, funny rpg, when you start, you need more.
Dungeon's Of Dredmor - AWESOMELY Done Tile based Rpg/Dungeon Rapist, Loads of humor inside. You can be mage of EMOmancy!
Intrusion 2 - This is some shit, Every platformer can hide now, This game is soo perfectly done... Best platformer ever played. it have physics and 3d, Very epic missions, and awesome music to cover it.
LIMBO - I do not know if it's still indie or not, good platformer.
Quintessence - The Blighted Venom - This one is Good RPG novel if you love that type of games, you should try it.
Towns - Awesome town builder game. Nothing to add.
Gnomoria - EVEN more awesome! you can build anything you desire here. Game is so much in shit that even when you make door or wall from other wood or stone, it have other color responding to it.
Rogue survivor - Zombie survival symulator, rogue like, 3D version is in development, propably will be good.
FREE Project Zomboid - Game which broke my heart, for first awesome, then updates getting out too slow and making lagg my pc, and every new update it just got more boring, Fear not, better inventory management system in development should fix it.
Frozen Synapse - You can call it new type of turn based squad shooter, good one also.
Faster than Light - Space ship simulator, sadly get's boring too fast.
Mark of the ninja - Best stealth platformer game on the market.