Ghost Master
 

It's one of those team-managerial thingy, you see you recognise, I bet.
Did not produce good numbers, but on giveaway it might worth a look.

Requiem: Avenging Angel
 

A good, somewhat original first person shooter.
Besides running around shooting down targets, you also gain special (magic) powers, like possession, or locusts (what is a fire-and-forget damage-over-tme thing).
It's a bit low on the frame per second (meaning computer sickness is possible), though still somewhat better than Doom and Quake, and the amount of ammo and enemies are well measured (meaning they give a reasonable amount for the average player, but that also means at times you'll see your quantities get close to zero - this is intentional), plus there's no creasy sommersaulting enemies, like in Quake.
It has a top-notch story for its time too.
The only negative I can recall is, I could never legitimately beat the boss.

The Night of the Rabbit
 

Some old-school point&click adventure game.
People said it's a bit too much walking around or something, I say it looks good enough to pay a couple bucks even for it.

Trüberbrook
 

Looks like some german point&click game. You can't rly go wrong with a point&click adventure game if you ask me. It has some paralell dimension running, like in Fringe. Fortunately this is not some wWII era game, though needs closer inspection what it is.

Blacksad: Under the Skin
 

Looks like some Batman-parody, but the game's page tells practicaly nothing of the gameplay.
From THIS video it seems there are quick time events for dialogue, "pixel hunting" for clues, and some interface you mess with the found clues.
If you are into the gamestyle, sure, otherwise maybe skip?

6 game bundle
 

Ok, it's technicaly not free, but so cheap, I must mention THIS.
I actualy prefer the "for 1$" treatment, that way people don't hit the "yeah, sure" button mindlessly, and hoard junk.