I found this on Quilter's Cache. It was a little box that said "Border Blocks" so I clicked on it & this is what came up. Hope it helps.
https://www.quilterscache.com/B/Borders.html
I first clicked on "Quilt Blocks Galore" on the site & then scrolled down to almost the bottom of that page. There is a block (just above the red block that says "**Missing Quilts Alerts!**) that is titled Border Blocks. Click on that Border Blocks box & you will see what she has on her site for border blocks.