There are a few commands for pacman that I tend to forget but find really useful. A full list can be found in the Arch Wiki.
# Search for a package to install pacman -Ss <package> # Search locally to see if a packge is already installed pacman -Qs <package> # List all packages which have been installed locally i.e. downloaded from the aur. pacman -Qm # list packages no longer required as dependencies pacman -Qdt # Remove a package and its dependencies pacman -Rs <package>