Beyond Yale, Wesleyan and Vassar, thanks.
Will be following.
As one approach, consider colleges at which the curriculum provides partial credit theatre courses for students with any prospective major. In practice this will seem much like an EC. As an example, Hamilton offers 141/142, which offer half a course credit per semester, and which can be repeated, presumably more than once, for additional credit: https://www.hamilton.edu/academics/departments/Courses-and-Requirements?dept=Theatre.
Kenyon College.
Bard?
Tufts has an abundance of ECs in theater, improv, and other performing arts.
If you are a planning to major in engineering or CS, Purdue has a ton of great theater ECs.