If you're searching for alternate phrases for "were member of," there are quite a few options that can help to spice up your writing and make it sound more varied. A few popular possibilities include "part of," "belonged to," "were affiliated with," "held membership in," and "were involved with." Some more specialized synonyms might include "had ties to," "were associated with," or "were involved in." Depending on the context of your writing and the tone you're aiming for, any of these alternatives could help to reinvigorate your work and make it sound less repetitive.