Of the historical mods, the 91 one is really good, as is the 97 one. 92 is a work in progress, but keeps getting better in every iteration. There are 93, 95, and 96 mods, but they're what I characterize as lumps of clay: tons of potential, but not a lot of refinement. There's also beta's of 98 and 99 out there, but they can be limited.
There's also several what-if scenarios if you want to check those out.