USA Parts Co.
USA Parts Co. sells 100% guaranteed all American made Harley-Davidson parts and accessories. The manufacturers range from small business to larger companies that sell internationally. They only sell Harley-Davidson parts and mostly Sportster and Big Twin parts at the moment. The Ricky Bongos Sportster front motor mount with key and coil relocation and his cv carb top with integrated choke mount are some of the best products I've ever seen.
DK Motosports is an awesome local motorcycle salvage yard that ships worldwide. I have run into them a few times at different swap meets and moto events. They have an eBay store where they sell all of their products. The inventory is always changing based on what they have in the shop and they have really great prices. The brands are always changing also, from Harley-Davidson, to Kawasaki, to Honda, to Suzuki and so on. You can watch their Instagram for the bikes they currently have on the lift to see whats going to be hitting the store soon.
We all know about Progressive Suspension. One of the best suspension companies out there and they have been around for awhile. But, what I know because I'm an epic motorcycle nerd, and you may not know is, they are always looking for assistance. They can't get a hold of every bike on the market though they try. If you know where to look you can find their bikes wanted page. If you have a model that they are looking for, can get your bike to La Palma California and are willing to leave your bike with them for a week, they will give you a full suspension set up for free. Keep your eye on their page because they update it every few months.
Just like Progressive Suspension, we all know Corbin. Also like Progressive, Corbin can't get their hands on every bike and offer a free seat if you have a model they are looking for and are willing to take it to Hollister California for a few days. Keep your eye on their page also, they seem to update every few months.
I surprisingly only found out about this one fairly recently. Revzilla has a scratch and dent section. It has parts for all motorcycle brands, accessories, and riding gear. All the items are are open box or blemished. I assume it's returns or shipping damages.