Next is King Kai. The blue catfish-man developed two special moves long ago. The first was the spirit bomb, an absorption technique that channels energy from all living things around the person using it, forming it into an energy 'bomb'. Very powerful. It's a pure-spirited attack, hence the name, thus bad guys cannot use it. It's been mastered by Goku and controlled by Krillin once or twice, and maybe Yamcha if I remember correctly.
The other move was too powerful for King Kai to control, despite the fact that he's the kai of the North Quadrant. It is, of course, the Kaioken, named after himself. He taught it to Goku during his first stay on his planet, who then made it his signature move. Kaioken is basically a power and speed-up, one which takes a harsh toll on the body of the user. It is so stressful that King Kai told Goku to multiply it no more than once, three times at the absolute most. Goku of course ignored this, upping it by three not long into his fight with Vegeta. It nearly tore his body apart.
As Goku's body got stronger, he was able to increase the power, going to thirty when he needed to escape an asteroid on the way to Namek. Kaioken is unique to King Kai, though there are other versions of the same principle around. Vegeta said as much when Goku used it on him the first time. "That Kaioken attack is a nice trick, but I've encountered something just like it before."
King Kai also has standard techniques such as materialization, telekinesis, and is familiar with the Instant Transmission.
Masenko - Looks like it was taught by Piccolo. One of Gohan's signature moves, it is fired from above the head with one hand placed on top of the other, assumedly for stability and control.
Special Beam Cannon - American, kiddified name of Piccolo's specialized attack that was developed after his tournament duel with Goku in Dragonball. Had very little effect on Raditz when he first appeared, but was devastating when his guard was down due to Goku's grabbing his tail all sneaky-like. ~_~
Manga name is Screwbeam Attack of the Devil, also Light of Death. I like these two names better, lol. A very concentrated attack, it consists of a beam of energy wth another beam corkscrewing around it. Charged by pressing the forefinger and middle finger to the forehead. Then you point and fire. Drills into the target, as evidenced with the two-in-one spearing of Goku and Raditz, a real coup for Piccolo. Mostly performed by Piccolo of course, but the two bad guys to absorb him, Cell and Buu, used it as well.
Kamehameha Wave- The most well known attack in all of DB/DBZ/DBGT, thanks to Goku. Most of the human/saiyan main characters have used it at one time or another, including Yamcha, Tien, Krillin, Gohan, Goten, and Master Roshi, its creator. It took Roshi 50 years to master it, and Goku only a day or so. A few baddies have used it as well, including Cell and Majin Buu. Chichi apparently knows how to use it, since she taught it to Goten. It's powerful enough to topple mountains, and it put out the fire on Fire Mountain, Ox-King and Chichi's home. Was named after the Hawaiian king, Kamehameha, and I read on this site that it was named by Akira Toriyama's wife. Blue in color.
Super Ghost Kamikaze Attack - "An attack dreamed up by children," as described by Vegeta. Gotenks' signature move. It's produced by hacking up ki through the mouth and blowing it up like bubble gum, forming autonomous 'ghosts' -- little replicants of the person doing it -- that explode upon contact with anything solid. The ghosts are capable of doing any ki technique the host knows. Used by Buu after he absorbed Gotenks; his ghosts fired Kamehamehas and the Gallic Gun, indicating that Buu can learn from observation, like Goku. That, or chibi Trunks knows the Gallic Gun, in which case Vegeta has been training with his present-timeline son. How sweet.
Vegeta's Big Three - The Gallic Gun, Big Bang, and Final Flash.
Gallic Gun - It was the first, assumedly invented as he annihilated planets for Freiza. It's arguably more powerful than the Kamehameha; very concentrated, this beam has destroyed worlds. Performed by dropping to one knee -- for stability, but can be fired from the air and whatnot -- and firing from the side of the body, somewhat like the Kamehameha.
Big Bang - A smooth move, fired from the palm of the hand with the thumb tucked in. Is basically a standard energy blast, spiced up as only Vegeta can.
Final Flash - Vegeta's latest technique in the Buu saga. Slowly charged, it's very powerful when ready and is a beam fired from both hands.
Death Ball - The Cold family signature move. Freiza's favorite, though it takes him a long time to summon it. It's worth the wait, as it's easily capable of destroying planets. Famous as the attack he used to destroy Vegeta-sei. Cooler uses it as well, though he's much faster about it, probably because he's *cough* stronger than his little brother Freiza.
Attack colors - Ever noticed how certain techniques seem to have different colors, or change in color when used by different people? I have. Buu, for example, is pink. His techniques are pink. Everything about him is pink. o.O;
From what I gather -- and what seems to make sense, kind of -- in the development of ki usage each person comes to associate a color of ki with themselves. When we first see Vegeta, his is blue. Most of his attacks are tinted blue, at least when he fights Goku. When he powers up to make a showy exit, the aura around him is blue. Come to think of it, the Kamehameha is blue most times, too. Perhaps Roshi's color is blue as well, or maybe blue simply indicates leading character for the moment. Vegeta's attacks are also yellow sometimes, such as the Gallic Gun, though yellow seems to be a standard for all fighters.
The Ginyu Force members have personalized colors, too. Ginyu's attacks are purple -- and I think Burter's may be too -- and Jeice uses red for his volleyball thing. Recoome's orange. Guldo...uh...I'm gonna ignore him. He sucks. LoL.
Of course, it could be that I've read too much into this and the creators simply wanted people to be able to tell the attacks apart, giving them different colors. *shrug*
Fusions - There are three that we've seen in the series, though in reality probably many more than that.
Namekian Fusion - The first fusion we are introduced to. Can only be done by Nameks and is permanent. The host body and mind is dominant, though the other can be summoned to speak at will. Physically performed by the dominant host touching the assimilated one and absorbing them, in a sense. Used by Piccolo and Nail, then Piccolo and Kami. Piccolo and Kami's union was partly fusion, but partly a reversal of Kami's separation from Piccolo's 'father' long ago.
Metamrese fusion - Well-known to the relatively informed, this common fusion can be done by any two people with equivalent power and body size, regardless of species. Lasts for 30 minutes at a time, after which the parties involved must wait an hour to do it again. Done by performing an intricate series of steps, the Fusion Dance. The Ginyu Force would love this technique. o.O;
Potara Fusion - Catch-all permanent fusion, can be done between any two people, with no exceptions. Performed by one person putting a Potara earring on the left ear, the other person wearing the corrosponding earring on the right ear. Their bodies are then joined to form a hybrid, stronger and faster than the original two. The voice is also a hybrid of the two originals. A kai fusion, introduced by the Elder Supreme Kai during the Buu saga.