Someone else's clothing can be used as a weapon against them; "jerseying" someone or yanking their coat down around their arms and then hitting them with a flurry of punches are street-brawler tactics that have been around for decades. Then, of course, there are BJJ gi techniques which translate well to fighting someone wearing a jacket...I bet the baggy pants favored by so many young wanna-be thug street punks are great for gi techniques.
Your own clothing can be a weapon. King Kabuki wears steel-toed boots; Savate or Okinawan-style kicks hitting with the point of the toe wearing those would hurt, and basic physics dictates that any roundhouse delivered with a booted foot should convey more force at impact regardless of how you land it.
I've known a few punks in my day who liked to wear lots of sinister-looking rings, which tended to have pointy things on them, to a) look badass and b) inflict more pain and damage punching. I don't know how it's done, but years ago convicts used to fashion rings out of cross-sectioned pipe while locked up which looked harmless by would open up massive wounds if worn while punching someone; time was you could identify an ex-con by whether or not he wore one of those.
As I've mentioned a couple of times already: any man's belt of sturdy design can, in an instant, become a ranged flailing weapon or a garrot to tie up an opponents' limbs and/or choke him.