Conex
Conex (formerly Taborama, not to be confused with Taborama in the Chrome Web Store) is now amongst my favourites.
Finding tabs across multiple groups (Tab Groups) and multiple windows
Around a month ago:
Conex is experimental, so proceed with caution.
I sometimes use it with Firefox 56.0, but avoid use of Firefox containers. Two screenshots below.
Seeking a tab with the location bar of Firefox 56.0
Not found:
Seeking the same tab with Conex
Found:
