Here is an incomplete list of aftermarket distributions, also known as custom firmware or custom ROM of the original Android operating system by Google.
I am sorry but this list is... not-good.
Includes problematic ROMs (Copperhead OS), dead projects (AOKP), and OEM closed-source ROMs (MIUI)
To anyone out there, my personal recommendation would be: if you own a Google Pixel, go for GrapheneOS or CalyxOS, if you do not have a Pixel phone, try LineageOS and derivates (I am personally running crDroid with microG instead of gapps)