The Bubble Walker is the primary mode of transportation for Krang in the 1987-1996 animated TV series prior to his android body's completion.
In the episode Four Musketurtles, some of Krang's contemporaries are seen using Bubble Walkers during a flashback. The Krangazoids also ride different-colored Bubble Walkers in Invasion of the Krangazoids.
Krang pilots a much larger, but similar body in a boss fight in Teenage Mutant Ninja Turtles II: Back from the Sewers.
The Kraang Walker is also very similar to a much larger Bubble Walker.