Rogere Federer, but also Rafael Nadal, Andy Murray, Kei Nishikori, Juan Martin del Potro and many others. Half-volley is perhaps the most difficult and complicated shot, that's why they are always incredible. It is a shot that is a mix of speed, strength and sensitivity, which often fails.
But when half-volley works, then the crowd and fans will be able to admire very exciting tennis moments. Half-volley is an effective shot on every surfaces, and against every opponent, especially for getting out of complicated rallies.
Here are the best half-volleys of the last few years in this video