You can stream all the content that you are allowed to post to Fansly normally; and the same restrictions apply as well. For examples of what you are not allowed to stream, please reference our Terms of Service: https://fansly.com/tos.
Make sure you own all the rights to the content streamed to Fansly (or that you have permission from the rightsholder to stream their content) – this includes background music, video game footage, etc.
If you intend to stream games on Fansly, please be sure to double-check the ToS of each game with their publishers – a lot of them may have rules against streaming their game behind a paywall, or featuring their game in a mature stream (read: streaming their game in addition to pornographic content). Please make sure to not break the terms of service of any game publisher while you stream on Fansly, otherwise your Fansly account may be at risk of being actioned.