It's May 1st - that means you get a new question!
How does River dress? Has that changed between his days as Sidestep and now? Does his specific villain career affect his wardrobe?
The official tags in game would be "Fashionable Military Surplus". Which is the best way I could think to translate the vibes of techwear.
River has always dressed mostly with comfort and practicality in mind. And comfort = layering for safety reasons for him. He always makes sure to wear at least his comfort color (shades of blue. if it wasn't obvious about the everything about him), or a specific comfort item (usually a favorite/gifted article. Like the pair of Ranger-merch socks he hopes is hidden in his boots at all times).
In the Rebirth days he wore exclusively hoodies, sweatpants (camo pants if he was feeling fancy), and boots (sometimes crocs.... dont judge him).
Now that he can afford it (stealing from banks and villains is a lucrative endeavor) River does dress with more intent of it looking somewhat good. Better fabrics, sturdy but able to breathe, more... fashionable? He wears a leather harness/holster situation now. For completely normal fashion reasons. Prommy (lying).
In the way of art. I tend to change up his tops but I always keep the color palette to same. And I always color in his socks with the color palette I use for Ranger suits. This villain wears Ranger Merch!