To list explicitly installed packages.
pacman -Qqe > pkglist.txt
Remove AUR packages from explicitly installed package list, and save to file
bash -c "comm -12 <(pacman -Slq | sort) <(sort pkglist.txt)" > native.txt
Install them on new system after selecting wanted packages.
pacman -S - < native.txt
List aur packages. Dont forget to edit.
pacman -Qmq > aur.txt
On new system, install.
pacaur -S - < aur.txt