There were 1" threaded steerer suspension forks made in the first half of the 90s--I have a little-used RockShox Judy from 1996 I would sell, but it uses a 107mm headtube. It takes a standard 22.2mm quill stem. Also have a very nice Marzocchi suspension fork with 1" threadless steerer I'd sell.
In the 90s there were also fatter-quill stems made for threaded 1.125" steerers, and even some fat-quill stems made for 1.25" threaded steerers--all rare now and worth avoiding unless you needed one for a fork you already have.
Search ebay for 1" / one inch suspension forks and see if you find one you like, but you're likely to find it in threadless form, as PedalUma suggests. Get a 1" fork you feel is an upgrade over the rudimentary one it has, and then get a stem to match it (probably a threadless stem). You will need a threadless steerer to be significantly longer than a threaded steerer that would fit, so measure your frame and desired bar height so you know what to look for.