Always bored to remember those:

• ArchLinux

  alias pkg-search="pacman -Ss"
  alias pkg-add="sudo pacman -S"
  alias pkg-info="pacman -Qv"
  alias pkg-files="pacman -Ql"
  alias pkg-list="pacman -Sl"
  alias pkg-which="pacman -Qo"
  alias pkg-depends="pacman -Si"
  alias pkg-depends-reverse="pacman -Sii"
  alias pkg-delete="sudo pacman -Rs"
  alias pkg-upgrade="pacman -Syu"
  alias pkg-update="pacman -Sy"
  alias pkg-download="pacman -Sw"
  alias port-search="yaourt"
  alias port-add="yaourt -S"
  alias port-update="yaourt -Syua"
  

• Ubuntu

  alias pkg-search="apt-cache search"
  alias pkg-add="sudo apt-get install"
  alias pkg-info="dpkg"
  alias pkg-depends="apt-cache --no-pre-depends --no-recommends \
                     --no-suggests --no-conflicts --no-breaks \
                     --no-replaces --no-enhances --installed depends"
  alias pkg-depends-reverse="apt-cache --no-pre-depends --no-recommends \
                             --no-suggests --no-conflicts --no-breaks \
                             --no-replaces --no-enhances --installed rdepends"
  alias pkg-delete="sudo apt-get --purge autoremove"
  alias pkg-key="sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys"
  

• VOID Linux

  alias pkg-files="xbps-query -f"
  alias pkg-list="xbps-query -l"
  alias pkg-info="xbps-query"
  alias pkg-update="xbps-install -S"
  alias pkg-upgrade="xbps-install -Syu"
  alias pkg-add="xbps-install"
  alias pkg-search="xbps-query -Rs"
  alias pkg-which="xbps-query -Ro"
  alias pkg-delete="xbps-remove -R"
  alias pkg-depends="xbps-query -x"
  alias pkg-depends-reverse="xbps-query -X"