Any Nitric Oxide product. Also, im sure caffeine/ephedrine and pretty much most stims will give an increase in vascularity. I will give you two words though that are tried and true methods.
yeah I float around 10-13 percent on and off cycle..wouldn't consider myself a lard-ass , that's fo shure! lol. I have noticed at night, even when I'm off cycle, my veins are protruding a lot...but during the day..normal...