The sites that I personally use the most are:
https://rutracker.org/ - A general tracker that happens to have a huge amount of VSTs and presets. To browse through the site you need an account, but you can use qBittorrent’s torrent search utility to search through their torrents, if I remember correctly. They have a file safety verification system, which is nice.
http://vsthouse.ru/ - An aggregate of several other trackers.
https://audioz.download/ - It offers direct downloads, which is nice for more obscure plugins which only have dead torrents. However, they use aids filehosts like rapidgator and katfile, so it’s never my first choice.
These are the only sites I’ve had consistent success with. Let me know if you can think of any others.