Plays:
Adding: Vanya and Sonya and Masha and Spike - Not a "small" or non-memorable role in this show - all memorable - well, maybe not Nina....
There may only be four characters in Who's Afraid of Virginia Woolf, but what a foursome!
Does, "I Am My Own Wife" count - one actor, but many characters!
Musicals are tough to judge - because of ensembles and more "small roles" than in a typical play. I'll nominate Fiddler, as even some of the smaller roles (Yenta, the Constable, the Rabbi) are strongly written and identifying (in my opinion) (Ok- Tevye's two youngest daughters barely exist). Whereas, in Into The Woods, for example, I don't think Rapunzel and her Prince and Tom's Mother are particularly "great" (in my opinion)