Each new plan includes built-in data through Maltego Data Pass and Credits to spend on Data Pass modules. Maltego Data Pass gives you instant access to a curated set of trusted data sources without the need to manage vendor contracts, API keys, or custom integrations. You can find details about the data providers included in Maltego Data Pass
here.
Each plan also provides limited or unlimited access to Maltego Connectors. Connectors let you integrate external data sources by adding your own API keys. With 100+ pre built Connectors, you can bring data from trusted third party providers directly into Maltego Graph. If your organization already works with external data providers, Connectors help you make the most of those existing contracts. You can see which Connectors are available per plan
here.