variety has 17 distinct synonyms spread across 5 of its 6 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a collection containing a variety of sorts of things
“a great assortment of cars was on display”
noticeable heterogeneity
“a diversity of possibilities”
(biology) a taxonomic category consisting of members of a species that differ from others of the same species in minor but heritable characteristics
“varieties are frequently recognized in botany”
a show consisting of a series of short unrelated performances
a difference that is usually pleasant
“he goes to France for variety”
Synonyms, antonyms and the broader and narrower relations for variety come from Princeton University’s WordNet. Full sources and licences.