So grateful for all of the dedicated coders and hackers in this space to keep our old Macs relevant and useable.

PowerFox has tweaks especially for Leopard and Snow Leopard and Mac-quality of life features. You can also try Basilisk, which is the upstream version without those tweaks.

Momiji is another variant targeting Mac OS Mavericks and other targets with ESR Firefox fixes. Works pretty well!

Finally, there is work being done to revive Safari for Mavericks and work to bring Netsurf to MacOS 9.