You should be able to do this without having to create your own widget.
In your Item:
- Click Add Metadata
- Click State Description
- In the Options field set out your options. For example, for a Number Item:
1=Blue
2=Red
3=Yellow
Once saved, clicking on the Item’s widget in the UI should then show a selection list.
It is a bit different than the mappings parameter in a Sitemap. And if you want clickable buttons rather than a list to select from (you kind of mention both) then I think you will have to create your own widget.