If you find a great video file in MP4, AVI, or WebM, you can easily remux (not re-encode) it to MKV without quality loss using MKVToolNix (free, open-source).
Steps:
This is perfect for taking free, legal MP4s (from YouTube or Archive.org) and packaging them as MKV for your Plex, Jellyfin, or Kodi library. mkvhub alternative free
These are not torrent sites; they are ad-supported streaming services (FAST). If you find a great video file in
The original RARBG is dead, but several "functioning" clones (like rargb.to) exist. These clones copy the old database which had exceptional MKV rips. This is perfect for taking free, legal MP4s
If you choose to browse MKVHub alternatives (specifically in the grey-area/torrent sector), you cannot do so naked. You need a specific set of tools to protect your device and your privacy.