Agatha was trying to build pocket watch clanks even before she lost her locket.
Dingbots often do helpful things without direction from Agatha, sometimes without her even knowing it. They seem best suited to assisting their mistress with mechanical tasks, though they can serve a variety of purposes; some can record and replay music, deliver messages, and presumably other things as well. Some, such as those built into the Battle Circus, could even self-detonate. According to the text accompanying the sketch , the last function was the first one conceived.
Most remarkably, however, dingbots are more or less self-replicating, though each "generation" is less well-constructed than the last, preventing them from replicating endlessly. Only the ones Agatha makes herself, such as Dingbot Prime, appear sturdy enough to last all through the story.
Because generally it requires a Spark to create a clank — that is, a machine with near-human-level intelligence — some fans, and even Tarvek, have speculated that Dingbots (at least the ones Agatha builds herself) have it. The ability to build a creature that has the Spark appears to be unique to Agatha.
So far in Act 2, the classic dingbots have not played a role; evidently they are all trapped in Mechanicsburg. However, Agatha's ability to build pocket clanks capable of housing an intelligence has served to enable her to keep first the Beast and now (a fragment of) Castle Heterodyne along on her travels.
There are two cards in The Works, of which there are three copies each, Agatha’s Dingbots 1 and Agatha’s Dingbots 2. Both cards have the details Machines, Clanks, and Pests. Dingbots 1 is the spherical one (similar to but distinct from Queenie) that is often used in Girl Genius contexts — it's the one on the Printable gift tags sheet. Dingbots 2 is a walking smokestack, similar to the Beast after it's been tamed, albeit with no arms and a larger stack.
Possibly relevant outside information
The Dingbots bear a certain abstract resemblance to the creatures known as "brownies" (more properly, "Watchmakers") in the 1974 novel The Mote in God's Eye, but without the (more) catastrophe-prone... aspect(s) (intentionally left vague to avert any additional Mote spoilers).