There are various breeds, thousands of them, and many aren't even tied to writing. Let's explore a well known plot bunny that has been positively identified.
The Lopearred Sitting Around Talking Shorthair
Physical Characteristics: Lop ears, short brown/grey flecked fur
How to identify his presence: When your characters inevitably come to a point where the plot simply won't advance, so they sit on a couch/the ground/ a golf cart/ a pirate ship and start talking about nothing in particular. Some couple thousand words later, a plot bunny pops up, grins, and heads off! It can always be discovered in this kind of plot stall, and it's known for waiting until the last possible moment (the moment when you are about to throw your laptop across the table) to come and create a diversion.