You can use pre-modifying expressions with unique. The OED says:
Unique - the only one of its kind; having no like or equal; unparalleled, unrivalled, esp. in excellence. Later also in extended use (especially with pre-modifying expressions): uncommon, unusual, remarkable.
Use in the comparative and superlative and with modification by words such as absolutely, fairly, quite, thoroughly, very, etc., has been criticized on the grounds that an adjective meaning ‘that is the only one of its kind’ should not be not gradable, but in many contexts this meaning is not readily distinguishable from the extended use. Examples:
1908 Kenneth Grahame Wind in Willows ‘Toad Hall,’ said the Toad proudly, ‘is an eligible self-contained gentleman's residence, very unique.’
1934 George Bernard Shaw On the Rocks Too True to be Good You don't appreciate him. He is absolutely unique.
2015 Sci. Amer. (U.K. ed.) Mar. 14/1 Spotted nutcrackers are fairly unique, even among seed-caching birds, because they rely on the seeds from just one kind of tree.