These are the people who find their way to the infant Jesus to pay homage. The shepherds, though, are sought out by the angels. The angels go to them to tell them the news, and then the shepherds come to Jesus. For the magi, however, no one goes to them with the news. They're only given a sign in the stars to interpret, a sign that hovers above Jesus.
I think this is an intentional contrast. Lowly shepherds are found by messengers, whereas the wise and wealthy are summoned from afar. This is a typical gospel inversion; flipping the natural hierarchy on its head by privileging the underprivileged and bringing the privileged low.
It would be too easy to start claiming that there is a third group missing from this story: the priests of Israel. The one group who should see and know that Christ was born is the group that is neither summoned nor found. I'm always a little cautious about deriving lessons from what's missing because it runs the risk of reading something into the text. Still, it's a curious omission.
Right from the beginning the gospel is good news for the poor, and hard news for the rich. Angels are sent to the shepherds, full of pomp and ceremony. No one is sent to the wealthy, who must search for themselves and then make a long journey to find Christ. Even with these little details, the framework is set for a gospel that goes against the grain of human society.