I think a good chunk of the Internet Archive is available as torrents, at least the software collections and public domain media.

You can also download a torrent of the whole of Wikipedia, with and without images.

AI model weights. Patches for MMOs (World of Warcraft famously used this to good effect).

I don’t think they do it anymore, but spotify started out with a p2p network on the backend.
Super smart way of bootstrapping such a thing without having to upfront huge server costs.

Not litteral torrenting but the protocols ar e very similar (since they are both P2P data sharing):

Windows updates can downloaded from other computers in your local network

Steam now tries downloading games from other computers you are logged in. You can opt-in thlo serve other accounts in your local network as well.

Downloading actual linux ISOs with bittorrent is soo much faster than downloading them directly from the distro’s mirror. I always use bittorent to download new linux distros I’d like to try.

Also, I believe p2p protocols are still popular in korea because ISPs there actually charge website operators for bandwidth delivered to korean customers. Twitch pulled out of korea because of this. I think their competitors there, e.g. AfreecaTV, uses p2p for their streams.

peertube uses bittorent to stream video.

PeerTube uses Webtorrents to offload hosting of hueg files.

Odysee uses something similar to do the same. (At least they claim to, but last time I took a dig at it it seemed to be hosted “regularly”)

Spotify famously had their own p2p-thing going in their desktop apps in the early days. Saved them a pretty coin back when hosting was expensive.

Coming to a browser near you is IPFS.

Clonezilla uses bittorrent for one of its massive deployment modes. I work at a university, and whenever we have to deploy an OS image, the ten gigabit uplink between the storage server and the classroom switches always gets saturated in unicast/interactive mode. Using bittorrent mode gets around this issue because once a computer has downloaded a chunk of the image, it can seed it for the rest of the computers within the subnet. One massive limitation is that the target computer has to have enough storage space for both the downloaded image and the deployed OS too.

One funny use I discovered when I was cloning a lot of computers is that even on a closed lan, BT with local discovery was stupidly fast in distributing a big set of files across a pile of computers instead of rsync. Also, setting it up was much easier.

There’s Syncthing and it’s proprietary counterpart Resilio that allow you to sync folders between machines and send individual files over p2p. Very neat software.

Any large file is going to be much quicker getting through BT as long as there are enough seeders. OS distros, patches, P2P files, 4K anything, etc.

IIRC Steam uses BitTorrent to help users download game assets. There’s an option to switch it off, still, so must still be going.

I podcast I listen to says that they used to distribute episodes by BitTorrent, way back in like 2006, as a way to keep bandwidth costs down when they were new. I’m pretty sure they had stopped that option by the time I started listening in about 2008/9.

Transferring files to several other computers. I’ve done it in the past before I used KDE connect to transfer files rather than use ftp or just memory sticks. It would be useful at a LAN party to get several copies of the software distributed. (Kinda piracy but doesn’t have to be if the game is free or everyone owns it legitimately).

I torrent old out of print books that I can’t find anywhere else. The scans are usually pretty good. There was also a podcast I used to listen to called Caustic Soda. When they ended it, they released all of their episodes through torrenting so the fans could have them.