Common suffixes:
* -ing: varying (present participle)
* -ed: varied (past tense and past participle)
* -ation: variation (noun, the act of varying or the state of being different)
* -able: variable (adjective, capable of changing or being changed)
* -ance: variance (noun, the amount or degree of difference)
Less common suffixes:
* -ly: variably (adverb, in a varying manner)
* -ist: variationist (noun, someone who studies variations)
You can also use compound suffixes like:
* -ation-less: variationless (adjective, without variation)
* -able-ness: variability (noun, the quality of being variable)
The specific suffix you choose will depend on the meaning you want to convey.