These are very simple, but if they're useful and you'd like more intricate or different-styled ones, I can do those in future.
These are free for everyone!
50W x 100H
75W x 100H
100W x 100H
Obviously, you can resize these as you see fit for your projects. I bezzeled the bottom edges to make it a little easier to get them off the build plate if you print them flat.
Enjoy!