Hello,
Yes, we have lots of yellow star buttons available on our website. If you just type in "yellow star" in the Search box above, a page will appear with your search results and there will be different yellow stars to choose from. You can also look in our Beads, Buttons and Charms category on the website as well and find them located in there. Here is the link to one that we have that would work well with this design:
http://www.everythingcrossstitch.com/large-bright-yellow-star-mrp-p39597.aspx?k2=e1
Hope this helps!
~Kristi @ ECS