What are the robotic enemies in Sonic games called?

The robotic enemies in Sonic games are commonly called Badniks.

Badnik is the traditional English name for many of Doctor Eggman's mechanical minions, especially the enemies from the classic 2D Sonic games. They often resemble animals fitted with weapons or machinery, such as the Moto Bug, Buzz Bomber, Crabmeat, and Caterkiller. In the early games, destroying a Badnik commonly released a small trapped animal.

The word combines the villainous idea of being “bad” with the name Robotnik, Eggman's former English name. In later Sonic games, Sega more often uses broader descriptions such as “Eggman's robots,” and many modern machines have individual model names rather than being emphasized as Badniks.

Badniks should not be confused with every robot in the franchise. Characters such as Metal Sonic and the E-100 series are distinct creations, while Badnik usually refers to Eggman's regular automated enemy forces.