Not all integrations are listed here, due to overlapping functionality or still being in development. The exporter default port wiki page also happens to include a few non-exporter integrations that fit in these categories.
For service discovery mechanisms not natively supported by Prometheus, file-based service discovery provides an interface for integrating.
The remote write and remote read features of Prometheus allow transparently sending and receiving samples. This is primarily intended for long term storage. It is recommended that you perform careful evaulation of any solution in this space to confirm it can handle your data volumes.
For notification mechanisms not natively supported by the Alertmanager, the webhook receiver allows for integration.
Prometheus does not include configuration management functionality, allowing you to integrate it with your existing systems or build on top of it.