There are also Servo and WebKit. Servo was kinda dead for a while, but the project was recently transferred to the Linux Foundation and revived by Igalia, with funding from Futurewei. Not suitable for daily use yet, but worth keeping an eye on. WebKit is of course used by Safari (which I guess makes it the second most used browser engine after Chromium), but also Epiphany on Linux. I’m not aware of any Windows browsers using WebKit. Fun fact: Chromium was forked from WebKit, which in turn was forked from KDE’s KHTML and KJS engines.
There are also Servo and WebKit. Servo was kinda dead for a while, but the project was recently transferred to the Linux Foundation and revived by Igalia, with funding from Futurewei. Not suitable for daily use yet, but worth keeping an eye on. WebKit is of course used by Safari (which I guess makes it the second most used browser engine after Chromium), but also Epiphany on Linux. I’m not aware of any Windows browsers using WebKit. Fun fact: Chromium was forked from WebKit, which in turn was forked from KDE’s KHTML and KJS engines.