How can I make irregular grid for strategy game?

Hello guys, Ive checked Unity Answers forum and some good tutorials about making grids for strategy games. Most of the topics are about making a hexagonal grids. But I cant find any solution for creating irregular grids like this one:

One of the tutorials shows how to make an irregular hex grids by using a randomization. But is there a way that I could hmm draw a border of every single grid field in Unity?
Could You give me any advice what should I check? Any class names in Unity, tutorials (that would be great). Thanks for your interest in the topic:)

If you don’t want a randomized map, you can do this in Blender or 3Ds or something. Take a plane, and just cut it with the knife tool. Make sure to add a different material to each so that you can individually assign them a different material as needed.