Yes it's possible, the details are in the link "Sharing Marketplace Content".
https://docs.mendix.com/appstore/sharing-content/
There are a few guidelines for widgets in the documentation that you must follow for it to be accepted for inclusion.
To develop widgets and submit them to Marketplace, follow these guidelines:
- The widget should be pluggable
- When writing variable and function names, use lowerCamelCase (for example, mySecondVariable)
- Add code comments
- Use descriptive variable and function names in both XML and JavaScript
- A function should not be more than 200 lines of code
- A function should only do one thing, and it should do it properly
- Use hooks and functional components over class components
- Create test pages for mobile when content is made for mobile platforms
Good luck!