You need to think about whether you want suspension or go rigid, and how high a front end you want. You can use any forks for 26" bikes if you're running discs or no brake at all, but with a higher front and longer wheelbase than using one designed for 24". Really the only 24" specific suspension fork around is the Marzocchi D-Street, but this won't suit everyone because it is 20mm through-axle and weighs something like 7 pounds. It will run 24" rim brakes though. You can use rim brakes on 24" wheels in some 26" suspension forks by using older Pace brake-mounts that clamp on to the lower legs, but you need to make sure the legs are the right diameter. This is probably not recommended by the manufacturers of most forks! If you want to go rigid with discs or with no brakes there is a fair selection of 26" forks that you can choose on the basis of front end height - look in specifications for the axle to crown distance. If you want to run rim brakes there's a bit less choice. If you're buying new/recent forks, Identiti Rebates have clamp-on mounts (for an extra £25!), these might fit other rigids too - check the diameter of the legs. The current Pace RC-31 clamp-on mounts (£35!!) will fit some rigids too. The Charge Nozzle has screw-in mounts to let you run brakes on either 24" or 26" rims at no extra cost. If you want an especially low front end you could try a BMX race/cruiser forks in 24" size - S&M Pitchforks for example have a very short axle to crown height. To show what can be done here's my bike rigid with 24" Rhynolites and Charge Nozzle forks with rim brakes and springy with 24" Sun SingleTracks, 26" Fox forks and discs Hope this is helpful!