So a few days ago I decided to pay around with some buttons and some blank cards and see what I came up with. I think if you want to make these button cards yourself it is easier to get a bunch of buttons and just play around with them and see the combinations that come out of that there is no strict formula.
This uses very simple paint (as in a line and a trapezium) and then adding the buttons on in size order. I used water colour pencils so I just coloured the shape in and then added water even the colour out.
Now this is a cute one for someone special. Using the heart shaped buttons and creating a heart.