On many bikes on this site.
Of buying then
On ebay for a lot of money, on Facebook, on other sites.
On here if you out up a wanted add with what you want, which you prefer, any particular year/colour.
And probably quite importantly the steerer tube length, threaded or not, and diameter.
I have a couple of nice Mag 21's awaiting rebuild when I get a buyer.
The forks are built to order to suit rider weight - fully serviced/tuned.
PM me if you're interested.
Cheers