Collocations for rare - adj.

be, seem
become, get
remain
be considered
19 species of the bird are considered rare.

extremely, fairly, very, etc.
especially, exceedingly, exceptionally, extraordinarily, incredibly, particularly, surprisingly
increasingly
comparatively, relatively
enough, sufficiently
The stamps were not rare enough to be interesting.

Rare is used with these nouns:
achievement, animal, appearance, beast, beef, bird, book, breed, case, chance, class, coin, combination, commodity, complication, condition, delicacy, disease, disorder, display, distinction, event, example, exception, failure, feat, find, flash, flower, gem, gift, glimpse, honour, illness, individual, infection, insight, instance, kind, lapse, luxury, mammal, manuscript, meat, metal, mineral, moment, mutation, occasion, occurrence, opportunity, phenomenon, plant, privilege, quality, sight, sighting, species, specimen, steak, step, survivor, talent, thing, treasure, treat, trip, variety, vintage, visit, visitor, volume, wildlife