I cut up the wonderful T Brace by Electrico so that it would work on the bottom left of the frame. The T Brace worked so well ... why fight a good thing? I could have done a nice rounded corner, but I kept it minimal. I added a small wall to the bottom side so the gap wouldn't be so visible.
If you installed any mainboard mod covers that extend to the end, please check to make sure this will not interfere with those. There is a notch cut for the board that rests up against the bottom wall, so if the mainboard has different spacers or something else that places it at a different location, the notch may not line up.
It's possible to print standing like it is or on its flat side (with supports everywhere). I chose to print on its flat side with supports everywhere. As one of the pictures shows - I left a very thin layer of support material behind for the tightest fit possible.
Important note: My Anet A8 has the paper still on the acrylic frame, and this fit snug. Since I cannot test this on an Anet A8 without paper, it might need adjusting for a paperless acrylic frame.
See other side:
See upper braces by Electrico: