hmm I would say my top 3 would be
1. Mist (similar to Agent 17 in some ways and is just generally a fun game)
2. Eternum (VN not much like Agent 17)
3. Stray Incubus (VN also not much like Agent 17, original dev abandoned it though)
Games with some similarities that I liked were
Insight of You (spend game corrupting boss, GF, and GFs BFF)
The Headmaster (also spend time corrupting people)
A Family Venture (also similar just more NTR themes)
Harem Hotel (very similar overall to Agent 17 just different visually)