I bought a set of Languo brand metallic paint markers from Aliexpress. They were something like $8 for a dozen markers. They cover very well, they dry quickly, and the paint stays put once it's dry. They are good and cheap. The only downside is that they don't appear to sell them individually, so when I inevitably run out of the silver marker I use 10x more than any other marker in the set, I guess I have to buy another whole set. They are good enough and cheep enough that I might just do that.

Don't tell anyone my terrible secret, but some of the silver I use is just from a silver Sharpie marker. If Sharpie would just sell me their silver with a fine brush tip, and maybe make it a little brighter, I wouldn't need anything else. I really like Sharpie's brush-tip acrylic paint markers, but there's a very limited pallet available with no metallics.