The Clock (Chronos) - Chronos is shaped like a clock and was named likely after the evil Greek god known for eating his own children and was killed by Zeus. Chronos wanted to stop all time.
Artsy - Artsy was a robot that enjoyed drawing and tried to paint everything in the city. He wasnt exactly an evil robot, though was destroying the city, so had to be combatted by Wordgirl. He was later redeemed and became a professional painter before it broke down. (Reincarnated after being killed by the Super Robot)
Nero - One of Tobeys robots with Brutus. It also was in part in destroying the city multiple times. It has likely been destroyed.
The Super Robot - A mechanically engineered robot used to fight Artsy. However, he started weeping and was reincarnated into robot heaven (like Enoch from the Bible)
Wordbot - See the full article on monster moviepedia
Checkmate 3000 - A robot used to play checkers against Captain Huggyface. However, he went mad because he didnt enjoy checkers.
Mouse-Zilla - A mouse that was mechanically engineered with Titanium, a rare strong metal, that was used to end WordGirl once and for all. He collaborated with Doctor Two-Brains to create this. This is likely the strongest of all robots they ever created.
Robot 2 (Tobey's Tricks and Treats) - A robot shown in this episode who along with Brutus takes a large amount of treats, only to find out that they are all toothbrushes (hilariously)
Robo Tobey - An athletic version of Tobey was created to wind the Field Day competition.
The Robe Robey - A robot that has a blue robe on him.