AC Milan
Arsenal
Aston Villa
Atalanta
Chelsea
Inter Milan
Liverpool
Lyon
Manchester United
Marseille
Roma
...and many other smaller clubs.
The Bundesliga, with it's strict ownership rules, is the last holdout (aside from Perez and LaPorta, who have plenty of secondary American capital and interests). Not coincidentally, the German teams were the only ones that didn't attach their blessing to the initial Super League proposal.