Flamethrowing Sentry, spins in circles spouting flames every few seconds. Short Ranged. (Back Burner + Refined Metal)
Soda Dispenser, gives Bonk! Atomic Punch! or Crit-O-Cola to scouts(cheap?) (Bonk! Atomic Punch! + Crit-O-Cola+ Refined Metal)
Laser Sentry, has a longer range than the other sentries. Could be upgraded from Flamethrowing Sentry.
Drill/Hammer/Better Wrench, upgrade speed doubles, 25%~ less health on user.
Grenade Sentry, shoots demogun projectiles. (Scottish Resistance + Refined Metal)