Musixmatch is, in my opinion, one of the better and more serious of the myriad lyric providers. Unfortunately they are still not on the Lyrics whitelist despite people asking for it since 2011.
Here is what looks like the most relevant proposal ticket, give it a vote if like me you would like to be able to add lyrics links from MM:
Musixmatch has been allowed since long time ago.
Maybe it’s just my experience but, most linked Musixmatch URL I come across are empty pages with no lyrics.
I suggested to remove Musixmatch support, but it has to be decided by someone else:
I ping you @reosarevok because someone has assigned the ticket to themselves, already and changed the status to In Progress…