Collection+JSON is a JSON-based read/write hypermedia-type designed to support management and querying of simple collections.
HAL is a simple format that gives a consistent and easy way to hyperlink between resources in your API.
This is a small subset of hypermedia definitions from HTML.
Siren is a hypermedia specification for representing entities, offering structures to communicate information about entities, actions for executing state transitions, and links for client navigation.
The UBER message format is a minimal read/write hypermedia type designed to support simple state transfers and ad-hoc hypermedia-based transitions.