Comment by HeyLaughingBoy

My go-to for stuff like this used to be SmallParts.com back when McMaster-Carr wouldn't sell to individuals (they do now). Amazon bought Small Parts and renamed it Amazon Supply. I haven't bought anything from them recently, but it's worth a shot.

Small Parts was amazing they specialized in, you got it, small components such as fasteners (you could get titanium screws if you needed them), small mechanicals such as tubing, solenoid valves, bearings, shafting, metal, etc. They were a prototyper's dream.