@kaia It's a Python reimplementation of JDownloader, I use it for large filesharing, when stuff needs to download overnight due to slow internet.
It can keep (http) downloads alive for hours without needing a running PC/browser and I can check it via phone.

Another one that's neat is filepizza. It allows two browsers to directly ad-hoc a p2p file transfer, without storing anything on the server. Useful for the, "I need to send you a file, but it's too big for mail, but I don't have cloud-storage/don't want it in the cloud." Happened a few times, saved me headaches.