Collocations for bench - noun

empty
long
narrow
hard
cushioned, padded
metal, stone, wood, wooden
garden, park
picnic
replacements', subs' (informal), substitutes' (all BrE,sports)
They have several top players on the subs' bench.

piano (AmE)

sit (down) on

seat

on a/the bench
She often sleeps on park benches.
He's sick of spending every game on the bench (= not playing).

government, Opposition
Conservative, Labour, etc.
back, front (Government ministers and the most important members of the Opposition sit on the front benches. Back-bench MPs have no official position besides that of MP.)

be on, sit on

from the … benchs
There were cheers from the Labour benches.

on the … benchs
Some MPs on the government back benches are starting to question the government's handling of the war.

work (usually workbench)
carpenter's, lab (informal), laboratory
kitchen (esp. AmE)

at a/the bench
He was working at his bench.