lol spray paint them.

I have this in my laundry room in the basement, and I just painted it to match the wall and it looks fine. I feel like a decorative plate would just bring more attention to them.

Home Depot has 421 1-gang and 2-gang toggle wall plates. I'd get simple, plastic ones that matched the walls. If you paint the covers, remove them to avoid painting the switches.

Note that the existing plates are not just cover plates - they support the switches. I think remounting the switches on extension plates and then using regular cover plates would look ugly. Embrace the industrial look!

Where are these ?

Thanks, all. They‘re in a finished basement.

I agree with spray painting them - maybe a glossy white to match the plastic switch toggles?

paint the box and the plate the wall color or close to with spray paint.

Ah, I hate to tell you this (not really!), but IMO painted brick is not a finished basement; the existing decor in your picture all matches.