The directional gibs.
See the backpack glow.
I shouldn't have touched it!

The Multi-Rocket ("Tom's Rocket")
The nail charge in action. Nothing beats the thrill of catching someone from across the room with this and spraying their body parts onto the walls.
The rail gun, shooting a player off of the ledge. You can throw someone pretty far with this.
The rail gun shoots through walls as well.
The force field. You can use this to block off areas, but be careful since it will blow you up as well!

Force Field plus Rail Gun. This is a handy and spectacular trick combining two Tom Mods. Also works (not as well) with the Backpack Bombs.
The Backpack Bombs in action once again.