"Card Type..." takes you to a particular category of cards (articles, books, etc.).
You can try it.
"Find..." looks for a particular card. Select the field to search from the pop-up menu. Common fields are listed on the pop-up menu, but with the "Pick Field ..." selection, you can pick any of the fields to search. After picking your field, you are asked for the text to search for. Note that institutions, schools, and the like, actually are in a field named "organization". The stack will beep if it finds nothing. Hitting return will repeat the search, unless some message have been displayed in the mean time. The "Repeat Search" can always repeat the last search. The "Find" button on this card works.