I liked the original idea by mlynch002, but I felt it needed more bolts holding it to the main frame of the Ender 3. I also strengthened the design when I noticed in Cura that some of the original sections were not fully connected. This is now a very solid piece that has definitely stabilized the Ender 3 Y-axis as I have noticed the machine is quieter.

I have printed 2 of these to mount on either side of the y-axis.

Hardware Used per bracket:
3x M4 T-nut
4x M5 T-nut (M4 can be used instead.)

3x M4x16 Allen Bolts
2x M5x12 Allen Bolts (M4 can also be used and a 10mm length should also work)
2x M5x8 Allen Bolts (M4 can also be used and a 10mm length should also work)

[Better pictures to come soon]