Yes, VARIANTS is a Scrabble word!

Letter values in Scrabble US: V 4, A 1, R 1, I 1, A 1, N 1, T 1, S 1.

Is it a valid word?

VARIANTS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

an event that departs from expectations
(biology) a group of organisms within a species that differ in trivial ways from similar groups
a variable quantity that is random
something a little different from others of the same type

Also: var., random variable, stochastic variable, chance variable.