Currently
CatsXP is fully supported. on W7+ (full feature updates, not only fixes)
Also the Palemoon browser is supported to W7+ (older Firefox engine but maintained on W7+)
Waterfox supports Windows 7 with Intel Core 2 or AMD FX. It is a 64-bit only web browser: (Firefox based)
Firefox 115 ESR (only fixes)
Hopping come fix for newest Firefox also.
But there are currently at least 4 browsers still supported in some way on W7+.
Firefox 115 ESR (only fixes)
CatsXP Browser (Chromium engine) (full updates)
Pale Moon (Old but maintained Firefox engine) (full feature updates, i think?)
Waterfox W7+ with Intel Core 2 or AMD FX. It is a 64-bit only web browser: (Firefox based)
In my opinion CatsXP is the best choice now.