Well, I do both -- coordinate and contrast. I wear almost exclusively Darn Tough merino socks, which come in a huge assortment of heights, weights, colours and patterns:
https://darntough.com/collections/women
I have a bunch of dark solid ones (black, purple, olive) that I'll wear with just about anything or if I want to match to footwear or pants. Then I have some bright patterned ones (striped, polka dotted, etc) for more of a "statement sock" effect. I work with young kids so if my outfit is otherwise "boring" I'll often throw on a pair of quirky socks. Most versatile of all are neutral but textured/patterned: black cable knit, charcoal/black stripes, etc. I feel more intentional about showing my socks when the socks have something going on.
Oh, and for true dressy, I have sheer black Wolford trouser socks. They're probably about six years old and seemingly indestructible, as Wolford is known to be. Some day I'd like to add another pair of sheer trouser socks with some sort of subtle pattern -- lacy floral or polka dots etc. I could never use sheer socks on a daily basis though (or cotton ones for that matter); I'd have frostbite on all my toes!