I used pcbs.io for the original run of black panels, but I highly do not recommend them. The quality is fine, but it takes about 1 month longer than they advertise.
If you don’t mind purple solder mask, oshpark.com is the best fab I’ve ever used for speed cost and quality.
For the attenuated version I’m testing out dirtypcbs.com. I’ve seen some boards from there and they are high quality (and you get 10-12 for about the same price as oshpark’s 3) This takes a bit longer than osh park, but is cheaper. I’m told to just be sure to use the DHL shipping otherwise it’ll get stuck on a boat for a month. Oh, and you can choose a bunch of options too like solder mask color, ENIG vs HASL, you can even order aluminum boards from them, which is an interesting prospect for a panel.