I'm talking about those characters who have a small screentime or even had little influence to story but despite that they're still remembered and some of them even developed their own cult following ironically and unironically.
For example:
FN-2199 aka TR-R
Bill Wilson aka CIA from The Dark Knight Rises
The Baseball Furies from The Warriors
The Gimp from Pulp Fiction
Note:If I've accidentally listed one of your favourites It's not a problem.