Collocations for indispensable - adj.

be, prove | become | make sb/sth
He had soon made himself indispensable.

consider sb/sth

absolutely | almost, virtually

for
Written sources are considered virtually indispensable for today''s history teaching.

in
These drugs are almost indispensable in the fight against the disease.

to
skills which turned out to be indispensable to her career