You can create an entity and then create two attributes “key” and “value”. Now a single object of this entity would provide you a key-value pair. Multiple objects of this entity will form a list. And from that list you can search based on key.
In addition to Umar’s comment, you could also create an Enumeration (for the key), and then use conditional visibility on your page to show specific content based on this (for the value).
thank you very much Umar & Robert