It's pretty simple, You choose 3 games for 1 CSGO Key or TF2 Key.
1 game in each list below:

[GAME 1]

1001 Spikes
3079 -- Block Action RPG
Across Flash
AirBuccaneers
Battle Forever
The Dweller
Edna & Harvey: Harvey's New Eyes
Mutant Mudds Deluxe
Northmark: Hour of the Wolf
POPixel
Splice
SweatShop
Tank Battle: North Africa
Tomb Raider II
Won't You Be My Laser?

[GAME 2]

3089 -- Futuristic Action RPG
Awesomenauts Cluck Costume
Burst
Electronic Super Joy
The Escapists DLC: Alcatraz
Hexoscope
Max Gentlemen Triple DLC Pack
Mystery Castle: The Mirror
Police Quest Collection
The Prism
Quadle
Run Rabbit Run
Stardust Vanguards
Tomb Raider III
Uncanny Valley
What's under your blanket !?

[GAME 3]

4089: Ghost Within
Base Squad 49
The Forest of Doom
GRID 2 Drift Pack
Gunnheim
Home
INK
Necromonads
Oniken
The Orb Chambers
Plantera
Road to Ballhalla
SickBrick
Skilltree Saga
Tick Tock Isle
Under Zero
Yelaxot