Berasategui's backhand = Youhzny's backhand in my opinion. They have the same kind of funky technique of being a hybrid one-two hander, i.e. starts off looking like a two hander but ends up a one-hander...weird. Youhzny's got more confidence in his though, and can be more offensive with it. Berasategui's backhand was consistent with decent rally pace, but it was way predictable and he never tried to do anything with it leaving him vulnerable if he had to hit it too much...would allow the opponent to dictate and move him around, tire him out so he wouldn't be able to smack his forehand, which I agree is one of the oddest if not most effective strokes ever.
As far as serve, Kaarsten Braasch no doubt. That is #1 the funkiest pro motion/technique of any kind bar none for the rest of all eternity.
Goran's serve is also rather unique, he looked like he was a figure skater slip-sliding on ice with it.
Becker's serve for its unique rocking pendulum motion, like a rocking chair, like a hammoc swaying...then boom...BOOM!
Edberg's service motion was unique as well due to the way he twitched his shoulder turn in the beginning and then arched his back so much.
McEnroe's a given.
Bruguera on his forehand and backhand. There's not a single player out there that hits their forehand the way he did, in spite of all the western grip players out there. All those guys tend to hit their forehands in the Moya, Ferrero, Gonzales style mode with the windshield wiper technique. His technique was as McEnroe stated, "beyond open." It was unnatural the way he kind of opened up his shoulders on the stroke and exaggerated everything to get wrist action and top. I honestly believe this to be the hardest forehand technique to emulate bar none.
Bruguera on his backhand was also weird because he had the cocked wrist take back, took it back like in a box beam. This to me made it a more difficult technique to emulate than any other two-handed technique I've seen. He basically hit it like a one-handed backhand player except with another hand attached. Stayed much more sideways through the stroke and planted his feet more deeply like a one-hander does, most two-handers rotate their hips more freely and tend to flick at the ball more or hit with a slighlyt semi-square stance whereas Bruguera hit with a closed stance. This was effective in that it enabled him to brush up for topspin if he was really prepared more so than others, but it was also effective on the pass where it seemed like his box beam takeback provided added deception and allowed him to "hold" the direction of the ball to the last second so to speak.
Korda's forehand was kind of funky too, in that it was SO flat his motion if seemed almost unnatural. His take back and everything seemed so rigidly linear, like an elongated Connors swing; but it was amazing because you just didn't know how he managed to keep the ball in the court like that, striking the ball so flat with an elongated swing.
I'd say Borg's backhand was kind of an anomaly the way he swept through the ball and let go with his top hand.
Santoro on his forehand, because unlike other two-handed forehand players he doesn't try to drive every ball, rather he seems to like to literally chop at every ball...he's basically the tennis equivalent of a knuckleball pitcher. Rarely an elite player, but an effective one nonetheless who on his best day can befuddle the mightiest and make them look silly.
Chang's two handed backhand was also kind of unique, because he had such a pronounced laid back wrist on it. It was really cool how he could just whip the pass shot-arngled cross court or up the line with such deception.
Muster's backhand was like something only the abominal snowman could come up with it, was like he hit it with a massive snow shovel. He just muscled through that thing like nobodies business. Never seen a one-hander rip a backhand with such velocity, it always looked like he was ripping his shoulders out on the shot. And his shirt was just ripped because of all the torque he was creating and the extent of his shoulder turn.
Pioline's backhand was also unique in that it was much more flowing and rhythmical than other one-handers. It was like he added hip-hop to his backhand, he was a break dancer with it in terms of his preparation, going through the top rock or "uprock" if you will...then he'd go for the kill. Most others it was the shot only, Pioline it was the dance first, the shot later.
Courier's backhand is obvious, but it's his forehand that also deserves honorable mention. He cocked his wrist on that forehand and with very little wind up muscled it home with just that, a cocked wrist. He just looked to me when he was hitting his forehand like someone who was holding his breath and gritting his teeth in absolute anger...the ball would receive the ultimate punishment when he finally pulled the trigger. In the final estimate, Courier pulled the trigger a lot. A natural born killer is what I would call him and his forehand.
Kafelnikov's forehand, I agree with for obvious reasons. It was the equivalent of Bruguera's box beam take back on the backhand.
But Kafelnikov's backhand was also unique, because he held his arms so rigidly. It was like someone put starch in Kafelnikov's arm and as if they were solid steal I beams, iron bars is what his arms were. And he pounded the ball precisely and without mercy as result.