R20Converter VS ddb-adventure-muncher

There is a converter from Roll20 to FoundryVTT. I've used it with great success:

https://github.com/kakaroto/R20Converter

Honestly, the only 2 times I would recommend you stay with Roll20 is if A) You are really insecure when it comes to computers as you will be hosting the server yourself (again, really simple with foundry, but it can scare some folks) or B) You are heavily invested in your 5E system and do not wish to import your campaign (though there is a tool to make the move from roll20 to Foundry much less painful)

I was a roll20 pro subscriber for 2 years and recently switched to foundry. It's light years ahead of roll20 in every category. Edit: there is a tool available to export your roll20 data and import it into foundry. Relatively easy to use but you have to sub this guys Patreon to get it. I did the low tear for 5 bucks and then canceled it so essentially it cost 5 dollars https://github.com/kakaroto/R20Converter

You can use this tool to export campaigns from Roll20 to Foundry VTT. Downloading the tool requires that you join Kakaroto's Patreon, but you can cancel the subscription as soon as you download the tool. Also, in my experience, Kakaroto is very responsive to people who experience issues with using his tools.

This tool will convert Roll20 modules to foundry: https://github.com/kakaroto/R20Converter

I cant believe no one has said this yet - but there’s literally a thing called R20Converter that takes an entire game in roll20 and dumps it into foundry, with everything setup as it was in roll20. https://github.com/kakaroto/R20Converter

and R20 Converter: https://github.com/kakaroto/R20Converter https://github.com/kakaroto/R20Converter/blob/master/README.md

DDB Adventure Muncher - Pulls in all things module

In addition to the R20Converter module mentioned by others, if you're doing commercially prewritten adventures there's now a module (in beta) that imports complete adventures from D&D Beyond into Foundry. It's also a paid Patreon subscription, but in principle you could get the $3 or $5 tier once and import all your adventures and then unsubscribe. If you got your prewritten adventures elsewhere or pre-wrote them yourself then this particular module won't do much for you.