Any fork will work in theory, but imo the frame is quite burly looking so I'd be looking for something that suits it looks wise. More modern forks have wider diameter stanchions so the lower legs are wider too, so may suit the look. Is it a disc or v frame? Plenty more options disc wise for 26 inch wheels, but v ones are out there. If it were me and v brake, I'd be looking for a reba or fox with v brakes or marzocchi I'd say. Air forks are lighter, coil more fit and forget.
You'll need a 1 1/8 steerer long enough of course, and travel to suit the frame. I'd guess 100mm to 120mm would work fine.