I subscribe to several YouTube channels, which cover tennis.
Jsnap2 features Pete Sampras highlights, neibaf3 primarily involves past Roland Garros exploits, and LleytonHewittTV speaks for itself.
The one I've watched the most lately would probably be ysdwdy, who offers videos from Stefan Edberg's prime.
I watch ysdwdy's videos the most because they are the most different from today's game.
Edberg, along with John McEnroe, is the most effective pure serve-and-volley player of the last 30 years.
When I say "pure S&V," I mean that as opposed to players like Boris Becker and Pete Sampras, whose volleys weren't quite as good, but possessed bigger serves and harder ground strokes.
Volleys were central to the the pure S&V game, especially to Edberg, who lacked McEnroe's lefty Gordian Knot of a service delivery.
For Edberg, the serve, the groundstrokes, and his swift, agile movements were all primarily designed to get him to net, where he shined brightest.
The same cannot be said for the top 100 players today, most of whom come to net to put away easy volleys set up by their big forehands.
The pure S&Vs like Edberg, Patrick Rafter, and Tim Henman, all of whom were great volleyers, have since retired. In fact, so have most of the those who were "merely" really good at net, like Sampras, Becker, and Richard Krajicek.
Let's take a look at some of the best volleyers left in the men's top 100, in no particular order.