Marlin 2.0.7.2 firmware for your Vertex Delta
Nothing special, no heated bed, but extra features enabled for quality of life
Psychokiller1888/vertexdelta_marlin2 (github.com)
Note that it uses a modded Ug8lib-HAL to support the custom Adafruit screen made by Velleman: Psychokiller1888/velleman-u8glib (github.com)