This is my design, re-uploaded here from Printables.

If you are using the built-in profile in Cura for the Anycubic Vyper, you are probably familiar with the initial priming of the nozzle off the front of the build plate that the printer does before each print. I designed this box to sit in the front left v-slot underneath where the nozzle primes to catch the extruded filament so it doesn't collect on the panel or fall into the crack. It also works to catch filament that oozes out when the hotend is heating up or filament that is extruded when loading filament. This model will fit next to the y-axis with both the stock V-slot wheels and the y-axis linear rail upgrade by Resset. I prefer to leave the T-nuts in the same direction of the slot, rather than locking the box to the printer, so that I can easily remove the box to dump the extruded filament into a waste bin.