I have a generic export/import screen for the developer tools in the roadmap for 3.1 or 3.2. You could generate either individual files with several things, items, rules, pages, widgets or could export them as a package in a single big YAML array. Then you can modify it and reimport it the same way.
It could be interesting to have “packages” like these shared in the community so when you import them you get all you need, items with rules directly interacting with them, widgets and pages etc.