In the 60´s, I´d go with Santana,Laver,Rosewall and Bueno, with some contribution from Pietrangeli.Krishnan and Gimeno, too
In the 70´s, we had Frew Mc Millan,Roche ( he had a great touch even if not being your typical finesse player),Orantes,of course Nastase,Panatta,Gene Mayer,Amritraj, mexican Raul Ramirez, brittish Mark Cox, the classy and elegant italian Bertolucci, Poland´s Wojtek Fibak, and Victor Pecci ( for some time) and, of course Goolagong and Durr among the women ( I´d also include here Rosie Casals).I think Evert was also solid as a dropshoter but not a classical touch player.Navrrtilova, when she became a complete player later on, was also capable of the best touch shots.Gerulaitis should also be included here and I am probably leaving out a fews.
Mandlikova, Jaeger,and for a while Bunge and Ruzici, and of course Mc Enroe,Krishnan and Amritraj are the most distinguished touch players of the 1980´s.And when Leconte and Gomez were on, they were as good as anybody else; I have seen Gomez make amazing volley or backcourt drop shots and was a great defensive lobber.Finally, Mecir, whose feeling was uncredible and, being such a particular player with an untransferable style, me thinks he fits perfectly in the description of a touch player.
In the 90´s, we had, of course Hingis and Kournikova, but I think Martinez,Sabatini and, at the net Novotna could also be mentioned with the best.As for the men, there were not classical touch players but the feel and sense of the ball Bruguera,Korda,Rios and Stich had was certainly pretty remarkable.
In the current times, Federer, Nalbandian and some french guys like LLodra and Santoro can be mentioned as having good touch.And a guy with a nice timing is also underrated Costa, the spanish FO champion in 2002 and one of the most watchable clay court players of his generation.
1970´s as a whole and the first half of the 80´s were clearly the greatest times for touch players.of course, wooden rackets helped a lot but Gene played with an oversized graphite...