Sorry for necroposting I guess but now there is. :wave: Even Letterboxd themselves say it's a good alternative (here's a proof 1, 2).
It's called RAWG and it has everything you might need. There's the largest games database (over 280,000 titles), there's your personal library that syncs games...
I recently discovered the subreddit with an interesting idea — to challenge yourself with playing 12 games in 12 months. I started that and beat Oxenfree in January. Here's the full list:
Oxenfree — January
Teslagrad — February
Valley — March
Contrast — April
Shank — May
Hidden Folks — June...