I work on Roll20 a bit, I have 20 packs, it works out to around an average of $10 per pack earned per month right now, obviously some sell better than others... so, that's a value of a commission or two a month at this point of development. It might be worth it to you but it may also hamper your promotion matrix, since giving away free non-commissioned maps likely brings in a certain amount of traffic that then turns around and hires you for a specific idea in the future, and you also have a Patreon where you would likely share maps that you would sell on Roll20, getting you both a split on whether they buy from Patreon or Roll20, but also access to both marketplaces... while I wouldn't discourage you from trying, as your maps will sell on there too, you might find it a frustrating division of attention from the Patreon that you're trying to build. The good thing is, it will create another income stream, as there are people who likely don't look any further than the Roll20 marketplace. I won't discourage you, just trying to give you an idea of what to expect. It's beer money, if you don't get a serious collection of work available and keep it coming.

Map's nice, by the way.