There are sites that has print your own. I don't have the links handy but a google search should bring them up. Also I found whole page stencils of each common size of HST at a quilt show. I prefer to print but a stencil is super nice when I run out of printer ink right in the middle! I have a 7/8" ruler that is so handy to cut strips to make my own. I have the 1/2" hst marker, the Wonder Cut ruler that makes hundreds of hsts in no time, Quilt in a Day hst ruler which is great for quarter hsts, a new HST maker ruler still in the package, Inklingo and
Triangulation
software, and the Go dies of the common size of HST. I use a different method each time I make HSTs. I enjoy having options! One method may not suit my mood at the time.