These are the triggers that a monster can activate in vanilla Doom.

1: DR Normal Door (Open-Wait-Close)
4: W1 Normal Door (Open-Wait-Close)
88: WR Normal Lift (Drop-Wait-Rise)
97: WR Normal Teleport
39: W1 Normal Teleport
126: WR Monster Teleport
125: W1 Monster Teleport
46: GR Door Open Stay