Like suggested by @kirbyzone on kirbys idea tracker on nolt a JSON Schema for Kirby would bring autocompletion and validation of the flexible blueprints to your code editor like SublimeText, PHPStorm or VSCode.
In the best case such a schema is published on the official JSON Schema store and thus becomes available in most editors automatically. But with Kirbys blueprints thats quiet a complex task. It took me more than 3000 lines of json to cover the
- four root blueprint types (file, page, user, site),
- all layout wrappers you can use in page blueprints (tabs, columns, sections, fields),
- all sections (fields, files, info, pages, stats) and
- all 31 fields including the new ones from v3.7
I created a preview version and would love to get your feedback and hope that the core team contributes as well – or even better – takes over this project one day.
This also ties in nicely with the highly requested (261 votes) blueprint editor since – well – your code editor will be able do most of that now. 
Follow the easy installation instructions from the repos readme to
- clone/download repo then
- tell your code editor where to find the schema file and to what folder to apply it to