Need help creating fake steam keys!

Hello there! I'm in need of several fake, "fun" keys for several steam games for a prank. I have only made a few, as example bellow:

Dark Souls II
Y0UD1-3DY0U-D13DY

Deus Ex
D1DNT-4SKF0-RTHI5

Half-Life 3
G4B3N-3W31L-C4NTC-0UNT0-V3R02

The Elder Scrolls V: Skyrim
4RR0W-T0TH3-KN3ES

I'll really appreciate any suggestions for games and keys you guys have. As soon as the thing is ready, I'll post here on the thread the link to it.

Please keep the real keys formats, as told by steam and seen bellow:

• AAAAA-BBBBB-CCCCC
• AAAAA-BBBBB-CCCCC-DDDDD-EEEEE
• 237ABCDGHJLPRST 23

Thanks for the attention, and I'm waiting for more fake keys!

EDIT: There're other valid key formats, you can check them here