Basilisk is a Firefox-like web browser from the PaleMoon team based on the Goanna (Gecko) layout and rendering engine.
While that description seems like a mouthful, don't let that scare you off. It's considered a beta, but much like Firefox, it's very stable.
Basilisk is very fast and works almost exactly like Firefox. The most significant thing here is that it is designed to look like pre-Servo Firefox. With the latest, fastest Firefox ever, it might be too late, but time will tell. After all, Pale Moon has done millions of downloads worldwide.