I found a few free ones here that work ok:
You need to drag the contents to the swatch panel to make a pattern swatch before using.
Thank you! Will I need to download it, or can I keep it open in two separate windows to drag? What steps should I take? Sorry for so many questions. Complete newbie here! 😆
Download it and open the AI file.
Copy the contents into whatever file you're working on.
Drag the pattern to the swatches panel.
The old "Divide into Grid" function could probably do miracles for you and produce all the squares in teh world you would need to fill based on random areas or more controlled designs...