One of my favourite supplies in my paint arsenal are my Molotow Markers, these markers are great at adhereing to pvc and abs figure bodys and well as soft vinyl. I tend to use these for doing tattoos on my action figures.
Molotow has a massive array of acrylic paint markers in a variety of sizes and colours, some of which are refillable. I buy mine from here https://shop.bombingscience.com/canada/graffiti-markers/brands/molotow-markers?gclid=EAIaIQobChMIstq8l9Du1wIVkK_sCh3jGArMEAAYASAAEgLHP_D_BwE