Bank contributes to film great bean variety (8)
I believe the answer is:
garbanzo
'bean variety' is the definition.
(I've seen this in another clue)
'bank contributes to film great' is the wordplay.
'bank' becomes 'anz' (I am not sure about this - if you are sure you should believe this answer much more).
'contributes to' is an insertion indicator.
'film great' becomes 'garbo' (I've seen this in another clue).
'anz' placed within 'garbo' is 'GARBANZO'.
Can you help me to learn more?
(Another definition for garbanzo that I've seen is " Word from Spanish meaning chickpea".)