retro
geo
para
auto
olig
ennea
pseudo
omni
ante
The prefix that fits the definition of backward or back is "re-".
Using the prefix pre to mean after is a false statement. The prefix pre means before, pregame means before the game.
The prefix "omni-" fits this description. It comes from the Latin word "omnis" meaning all or everywhere, and is used in words like "omniscient" (all-knowing) and "omnipresent" (present everywhere).
The prefix that means "backwards" is "retro-".