Lyrics for YouTube от James Fray

This extension adds a new button to every YouTube music player. Press the button to search for the lyrics of your favorite songs and display them below the video player without leaving the page or pausing the video streaming while searching for the song lyrics. There is no floating window or caption-like lyrics instead the lyrics are displayed below the actual player. There is a link to open the current lyrics in lyrics.com as well. The extension uses musixmatch free API to find the lyrics among +7M Lyrics in 32 languages.

Note that in oppose to the some other similar extensions, this one only looks for the lyrics when they are requested by the user. There is no constant background activity or unnecessary remote server calls.