Lots of awesome links in the megathread, but I have yet to find a good source for content in languages other than English. Specifically movies/series in German, either as the original VO, or dubbed.
Are there any torrent or DDL sites where it is easy to find German stuff?
There isn't much on it in general, but I see german stuff on i2p a fair amount. I wouldn't use it if what you are looking for is too obscure but if you ever get bored and want to try something a bit different it is an option.
If you know the Usenet, I can recommend https://scenenzbs.com/
You will need a downloader and an Usenet provider, besides the indexer I shared. It can be linked with *arr similar to torrent downloader/indexer