Imagine two lists:
Each of those lists has several dozens values.
Is there a known UI widget that gives you the functionality to macth elements from one list to elements in the second list in a nice visual way?
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As I said: It depends on the purpose.
E.g. if the second list is supposed to "describe" the item in the first list. Set property, you could show the second list as a combobox next to the items in the first list:
Or, you could simply show each lists different listbox and add a "pair"-button:
You need to know what the user is trying to accomplish, and you need to know what the users mindset is like when this task is about to be done. This can be figured out trough task analysis and workshops etc. When you have created something that you believe is the best solution you need to test the solution with a few user to verify that the users gets it.