Hi Nick,
Many thanks for the feedback, just to be clear I'm not looking for any material unless it is strictly legit, I am however interested in public domain/free assets as well as substitute token packs as you have suggested with your very useful links and I'll be looking through those in detail as the app you suggest for making tokens.
I'm relatively new to Roll20 as a GM (been a player for a while) and I haven't gotten to grips with creating character sheets, so am looking out for a SB3 and/or Corum character sheet with the dice rolling mechanism embedded as I have experience during play of CoC7e and D&D5e.
If no one has one they can point out to me that is legal to buy or share then I'll fall back on using SB5e as I'm planning to present Madcap Laughs to a group of friends who are also fans of all things MM.
Keep well,
H.