Plenty of games on sale.
I can see reductions of up to 85% off: Psycho Pass: Mandatory Happiness: $5.24: https://store.steampowered.com/app/522880/PSYCHOPASS_Mandato...
Have a browse of the games to see if there is anything you like. Steam even sorted them in categories such as Horror, Sci-Fi etc.
Not sure if the sale hase "complete your collection" feature enabled.