Collocations for imaginable - adj.

be

barely, hardly, scarcely (esp. BrE)
To such poor people, the idea of having a choice of food is barely imaginable.

the best … imaginable, the most … imaginable, the worst … imaginable
It was the most boring movie imaginable!
They live in the worst conditions imaginable.

every imaginable sth
They had every imaginable shade of green.
They had every shade of green imaginable.