Hongkiat have a post with a list of 80 Video game wallpapers.
It is categorized to 12 groups
1. Fightings
2. Action Adventure
3. Role-Playing Games (RPG)
4. First-Person Shooter
5. Multi-player Online
6. Platforms
7. Racing
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8. Real-time Strategy
9. Simulation
10. Brawlers
11. Music Video Games
12. All Stars
You can see it here.