I have a collar obsession LOL.
CollarMania.com is my favorite for fabric. Everything can be custom and sooo many fabrics to choose from.
Paco Collars and
Ella's Lead are my favorite for leather.
Green Trout Outfitters are my current favorite leashes.
Zee.Dog looks cute but I don't own any (yet lol).
Check Etsy as well - many collar makers on there among other dog products!
Buddy Belts are popular harnesses (YT member Kristin (maximo) is a seller) and I love our Puppia harnesses. Ruffwear makes good outdoorsy stuff, as does Hurtta and Ezydog....
Most of the time, Jackson does not wear any clothes. He doesn't really mind them though. I put jackets and sweaters on him in the winter. He really only gets cold when it's like under 32 degrees F or if it's real windy or rainy etc out... But no problem putting cute outfits on pups for photo shoots etc! I think people get too worked up over it.