The most common and most likely answer to this crossword clue is the 5 plus 10 letter word STOCK CHARACTERS
S
T
O
C
K
C
H
A
R
A
C
T
E
R
S
Buddy explains!
The straight part
We know that "Familiar roles" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case familiar roles = stock characters.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.