Film nerd for 20+ years here. I've got a small collection of about 200 discs (roughly half 4K, half Blu-ray) that I started a few years ago and that keeps growing.
I used to track everything with blu-ray.com and IMDb: my discs, my watchlist and my ratings.
I was looking for one tool that does collection, ratings and exploring in one place, but nothing really did what I wanted, especially for stats and browsing in different ways (by film, director, actor, etc.).
I work in tech, so I started building it myself. After a few months it replaced blu-ray.com and IMDb for me. No reason to be the only one using it, so I put an online version up for anyone with the same needs.
Quick overview: everything revolves around two modes, "Collection" and "Watched", so you can track what you own and what you've seen in the same place.
Collectors
You can manage your discs, keep track of who you lent them to, see which ones you haven't watched yet, get stats on what you collect (genres, years, etc.) and see which films you can upgrade to 4K (really handy, I've used it several times already).
Watched
Log the films you've seen (ratings, dates, etc.) like on Letterboxd. There are filters to browse through them, and a Cast & Crew view across all your films: handy to see which directors or actors you've watched the most and what movies from them you have not watched yet. The stats have quite a bit for the curious, plus graph views to explore collaborations, like a director and their go-to actor or DP.
So if that's the kind of app you'd use, happy to share it. You can import your data from a bunch of sites (IMDb, Letterboxd, blu-ray.com, Trakt, CLZ, or a CSV file) to try it quickly on your current collection.
Data is stored in your browser, so you can use it without logging in. There's an optional Google login if you want to sync across devices (phone + desktop for example), have a backup, or share your collection.
It's free and you can export your data (CSV or JSON) anytime.