All in all there exist 3.944 combinations to achieve a perfect leg in 501, usually you'll see the following ways:
180, 180, Triple 20, Triple 19, Double 12 - that is the most used way, the mainline
180, 180, Triple 20, Triple 15, Double 18
180, 180, Triple 17, Triple 18, Double 18
Less common is the following line:
167, 167, Triple 20, Triple 19, Bullseye
https://www.globaldarts.de/globalDartsEN/sport/Outshots/ninedarter.html