There are irregular adverbs as well! The adverb of good is well - She's a good performer. She performs well.
Some adverbs are the same as their adjectives.
Fast (snel), fair (sportief/eerlijk), low (laag), high (hoog), hard (hard), long (lang), late (laat), loud (luid) en straight (onmiddelijk) - He's a fast driver, He drives fast.