This is a super easy and inexpensive to do DIY. The colours and use are also customizable.
All you need is a selection of paint chips, a frame, glue, paper, and a white board marker and eraser (you could also just use a wet rag).
Simply arrange the paint chips and glue them onto a piece of blank paper. Then place the paper in the frame and start writing. That’s literally all you have to do.
Have a good day!