I'm always down to more zaps. As for the feature, I plan to implement 3.

1.

As you wished, "contact/star/favorite" kind of list of pubkeys that the user can save as an encrypted event over the network.

2.

The user can pin some contacts and they will always stay at the top of the list for quick access.

3.

To expand this feature further, allow users to defien their own contact groups or add tag to each contact.