I thought that too! If so how many variations are there...?
I adapted an idea called "Recursive division" for generating a maze. Here's the idea for grids of square cells:
Take a piece of chequered paper (aka. grid paper, the paper you use for doing math, a grid of squares). Imagine that all the cell edges can either be solid "walls" or open "doors".
Now fold that paper along any line of cell edges. You get two smaller areas that have the fold line in common. Assume that you already know for both smaller areas that within each area, each cell can be reached from each other cell. Then this will be true for the whole paper, too, if the whole fold consists of walls except for just one door on the fold line. (Why? We already assumed that you can travel from each cell to each cell if those cells are within the same area. To travel from one area to a cell in the other area, first travel from the source cell to the cell that is next to the fold door. Cross areas through this fold door. From there, travel to your destination cell.)
So do exactly that after creating your fold: Make the whole fold into walls, then randomly choose just
one wall on the fold and make that a door.
Now repeat that for each of the two smaller areas separately: Fold the area somewhere, make all the edges of the fold into walls, then open one door on the fold. You get four areas that are even smaller.
Rinse, repeat for ever dwindling areas until each area either contains two cells or just one cell. If the area has exactly two cells then connect them with a door and you are done; if it consists of just one cell, you are done.
Here's a good description of the algorithm.
Here's a page that will show this algorithm in action visually (and lots of others, too).
I've adapted that idea to hexagonal grids with the following idea. In a grid of squares, you have TWO angles for the folds to choose from: A fold can be either horizontal or vertical. In contrast, there are THREE angles for the folds to choose from in hexagonal grids. This means that the folding operations can yield "irregular" shapes, and you must take great care to keep track of just what cells are on both sides of the folding lines.