Here’s a quick list of PCB fabricators with my own notes against them
OSH park – united states
Good for small PCBs. Great online PCB visualisation tool which I regularly use. Purple boards. Edges need the break off tidying up when you receive them.
Seeed studio – China
Used without any issues.
PCBs.io – United states
Produced as standard ENIG (gold) with black solder mask and white silkscreen. Visualise your PCB in the website and share them with others. When others have your PCB produced you get a discount on your next purchase which is a nice feature.
Elecrow – China
Very cheap. Reasonable PCB quality. Used this company twice now.
Wurth Online – Europe
Good quality PCB from brand name company. Somewhat complicated PCB choice and design rules. Professional PCBs.