Do I already own this game, and where? gamecheck searches your owned-game libraries across Steam, GOG, Epic and Amazon and prints any matches with the store they're on.
I've been working a bit and have good cli output:
# List all your games
$ uv run gamecheck list | head -n 11
493 owned games:
- 1000xRESIST [steam]
- 9 Kings [steam]
- A Knight's Quest [amazon]
- Active Soccer 3 [steam]
- Against the Storm [steam]
- Age of Empires: Definitive Edition [steam]
- Alan Wake Remastered [epic]
- Albion Online [steam]
- All Will Fall Playtest [steam]
- Alone in the Dark 1 [gog]
# Fuzzy matching
$ uv run gamecheck storme
Found 2 matches for "storme":
- Against the Storm [steam] (82%)
- Flashpoint Campaigns: Red Storm [steam] (82%)
# Which game do I have more than once?
$ uv run gamecheck duplicates
Found 12 games owned on multiple stores:
- Europa Universalis IV [epic, steam]
- King's Bounty: The Legend [gog, steam]
Let me know if you have specific feature requests!