Are we talking 28/38/48 range rings? Old XT should be fine, but so should lots of SunTour models. I have a NOS XCE that I could part with. XCD, XC Pro and Comp - all should work fine. Just avoid the ones intended for Microdrive cranks unless your big ring is a 42 - in which case you should look for a Microdrive model.

I've also used Campagnolo 9 speed triple FDs successfully on older setups. A bit hard to find in 28.6 but you can use a clamp adapter with a braze-on. I have lots of 3X C9 FDs on hand if you want to give one a try.