This is a personal memo to remember my little and simple trick (with Steam shutdown and installed from deb packages):

cd ~/.local/share/
mkdir -p /media/pofilo/SSD1T/Games/steam/.local/share
mv Steam/ /media/pofilo/SSD1T/Games/steam/.local/share
ln -s /media/pofilo/SSD1T/Games/steam/.local/share/Steam Steam