Lessons on ROLL20 and ethics.
Roll20 locks content behind paywalls. They lock stuff like fog of war, dynamic lighting, blah blah blah. They do not however -really- lock the content. Instead they just toggle a little thing on your browser and enable it.
A program called tampermonkey allows you to just turn on everything with the appropriate script.
Should you feel so inclined you could run this program, gain access to every single adventure module on the website, and proceed to port it using one of several modules that allow you to import entire campaigns from roll20 to foundry. Ostensibly these modules are to remove transition pains or to allow people to buy roll20 adventures and port them or use this script and port them.
Once ported you will have all tokens, all maps (with walls), and all the handouts etc etc that you would have with the roll20 adventure module.
There is also a module to port characters or NPCs from dndbeyond into Foundry so the character or monster sheets are within the platform instead of say on dndbeyond (how I run my games).
The group that maintains the tampermonkey script to enable roll20 paywall removal has stated they are switching to supporting foundry going forward. Foundry is kind of taking the vtt space by storm with a lot of creators opting into its environment.
https://www.patreon.com/kakaroto
http://vttassets.com/
edit - Note if you do not want to circumvent roll20 paywall and do not want to BUY roll20 adventures to port VTTassets.com is creating adventure modules with community created VTT ready maps with walls, lighting, notes, etc etc even tokens.