For me, Google video search, Google books (Internet Archive is good, but doesn’t always have the same stuff), Adobe InDesign (but in the process of learning LaTeX), and Typewise. As for the Google stuff, I liked Whoogle a lot, but almost all their instances seem to have been blocked or shut down. Also, apologies if this is repeating an earlier post.
Jellyfin is FOSS. You can by the way just install it and point it at your library to see if it recognises everything. It won’t change your file layout. If you have your movies named "title (year)“ and series in a folder format like “series title/season x/s0xe0x” (x being season and episode numbers), it should actually automatically recognise it all.
But I admit, if you have deviations from that you would need to correct those first and it seems from what I read that Plex is not as picky with that as Jellyfin is.
Misidentification is easy to fix in Jellyfin, with a couple clicks you can completely fix all metadata if it gets something wrong.
Well, I’ve tried it since this comment, and I’m using it occasionally (primarily because I like the Delfin app for Arch Linux), but there’s a lot of reasons I still prefer Plex. First and most importantly, I use PlexAMP as my primary music player and I have 1tb+ of music that I don’t feel like perfectly setting up again. It’s a huge amount of work, and I listen to a lot of lesser known shit that just isn’t easy to gather data for, and a lot of Various Artist shit that I’m really particular about how it shows up.
The other big issue I have is that Collections is a separate tab in Movies, rather than being listed alongside the rest of my library like in Plex, and that’s really just not useful for me. It automatically populated my collections just fine, but if my primary Movies tab is just gonna list each individual movie and I have to actually go to the Collections tab to see collections, it’s just not how I like my library. If I can find a solution for this it’ll go a long way to pushing me toward JellyFin.