BakaBT is a private tracker that has lots of high quality anime/manga artbooks, soundtracks and extras like that. That’s all I use aside from Nyaa, but my needs are pretty basic in general

My use case: I like to have all my emails stored locally just in case some disaster happens with the copies in the cloud; I also get to have both personal and work email addresses, from different providers, in one organized and unified interface, and the same goes for tasks, calendars and contacts; and some features from big web clients are sometimes too nosy for my taste (suggested replies, pushing their calendar, messaging, tasks and contacts products, etc)