Extract all key names and their possible values from any node

### Feature Idea

Hello,

I need to extract all key names and their possible values from any node, as seen in the UI. My goal is to use this information to build a custom node. Is there a way to achieve this, or is there an existing custom node that can handle this task?

Thank you for your help!

### Existing Solutions

_No response_

### Other

_No response_

Start by reviewing how node key names and possible values are represented in the UI and how custom nodes consume node information. The issue does not identify files, tests, or an existing entry point; done would require a defined way to extract this information for any node and use it when building a custom node.

Written by the indexing model from the issue text.