I can't take credit for designing this Nema17 mount as it was first made by @CreoTek (https://www.thingiverse.com/thing:3083500)
Only change I've made was to add another support on top of this bracket to stiffen it a bit more to make sure it is not bending under pressure of tightened Y-axis belt. This version is to be printed the same way as oryginal.
Just noticed that there's 2mm of top bracket that are blocking bed carriage from hitting endstop. Just remodelled it and printing new version now. This updated version works great. Got it installed now on my Ender 3.