This is a list of attacks from Dragonball Z/GT.

Arm Extender*:Used by Piccolo, this is the ability to extend his arms to grab his opponents for a surprise attack. All Nameks have to ability to do this.
Bakuhatsuha:Used by Vegeta and Nappa early in the Z series, this creates a ball of energy around the person destroying everything in it's area.
Body Change Beam*:Used by Captain Ginyu of the Ginyu force, the Body Change is an attack that switches bodies. By shooting a special beam, whoever gets hit switches bodies with whomever shot the beam. The two people gain the new person's speed and strength but not their knowledge of attacks or their ki.
Big Bang Attack:One of Vegeta's signature moves and most powerful attacks, the Big Bang Attack is a large energy projectile that can destroy just about anything.
Bukujutsu:The ability to fly using one's ki.
Burning Attack:Mirai Trunks' signature move, the Burning Attack is a powerful energy blast from the hands. I am unsure whether Trunks in the GT series is able to perform this attack.
Cannon Beam*:See "Makankosappo"
Chonoryoku:One of Chaozu's psychic abilities, the Chonoryoku allows temporary control of the opponent or causes some internal pain.
Chobakuretsumaha:Possibly Piccolo's most powerful attack, the Chobakuretsumaha creates a large energy blast destroying all in it's way. (In the DBZ games, it is known as Gekiretsukodan because it looks the same).
Daichiretsuzan:One of Freeza's most powerful attacks, the Daichiretsuzan is an invisible beam that cuts through anything in it's way.
Death Ball*:Possibly Freeza's most powerful attack, the Death Ball is a small (sometimes medium) sized black ball that is used to create mass destruction. Since it is so slow compared to other attacks, it is usually not used except for destroying planets.
Destructo Disc*:See "Kien:Zan"
Dynamite Kick:Mr. Satan's signature move, the Dynamite Kick is a kick that is completely worthless. Whether or not it's a strong attack on human opponents is another story.
Enerugii Kyuushuu:The Androids' signature move, the Energy Kyushu allows the androids to absorb their opponents energy and ki through holes on the palm of their hands.
Eye Beam*:A small but decent attack where energy beams come from the eyes.
Final Flash:One of Vegeta's signature moves and most powerful attacks, the Final Flash is a powerful blast used to finish off an opponent quickly.
Finish Buster:One of Mirai Trunks' attacks, the Finish Buster is a quick and powerful move used to finish off an opponent quickly.
Food Change*:Buu's signature move, the Food Change is an attack that changes opponents into other objects (with Buu, it's usually food). After being changed into food, they can be eaten.
Fusion*:The ability to fuse two people into one by performing a special dance. The new person will hold attributes from both people such as strength, speed, ki, attacks, looks, and even clothing. The fused person will last for 30 minutes before they separate into two. However, the two people who fuse must be approximately the same age and strength. Also, the dance performed can also be done incorrectly, thus fusing the two people into a weakling for the next 30 minutes.
Galick Gun*:See "Galick:Ho"
Galick:Ho:Used by Vegeta, the Galick:Ho resembles the Kamehameha, but is less powerful. The Galick:Ho is Vegeta's adaptation and counter against the Kamehameha.
Gekiretsukodan:Used by Piccolo, the Gekiretsukodan is an large energy projectile shaped like as sphere.
Genki:Dama:One of Gokou's signature moves and most powerful attacks, the Genki:Dama is a ball produced from the ki of all living things. This attack takes the longest to charge out of all the attacks in the entire Dragon Ball series. This attack is also known as the Spirit Bomb.
Hasshuken:Used by Gokou in the Dragon Ball series, the Hasshuken is the ability for Gokou to grow more arms so that he ends up with eight arms allowing him to attack better.
Jibaku:A self destruction technique, a very powerful attack but the user can not survive. Only Cell and Chaozu have this ability naturally. The androids had a Jibaku attachment originally before it was removed.
Jinruizetsumetsukogeki:Used by Buu, the Jinruizetsumetsukogeki is an attack which fires multiple beams, each seeking it's own individual target, however, the attack takes a while to charge.
Kaioken:Used by Gokou, the Kaioken attack allows Gokou to gain a temporary boost in power and speed. However, after excessive use of the attack, the user becomes extremely exhausted leaving him prone to attack. There is also a chance the user will spontaneously explode from the surge of power.
Kakusandan:A relatively weak but diverse attack, the Kakusandan is a ki blast fired into the air where it will split apart into multiple ki projectiles whereupon raining down on multiple enemies.
Kameamea*:This is either the English name for the Masenko or a shorter name for the Kamehameha. (I am unsure which)
Kamehameha:One of Gokou's signature moves and most powerful attacks, the Kamehameha is an energy blast that is usually used for projectile countering purposes, as it is much too powerful to use in any other situation. Able to destroy mountains and even the entire world, the Kamehameha must be used carefully and be timed correctly.
Kamekameha:Goten's adaptation of the Kamehameha. Gotenks also uses this attack as he is part Goten.
Kamikaze Ghost Attack*:Possibly Gotenks' most powerful attack, the Kamikaze Ghost Attack allows Gotenks to create several "Gotenks ghosts," each of which has their own minds. Each ghost then causes severe damage when they come in contact an object.
Kien:Zan:Krillin's signature move and most powerful attack, the Kien:Zan is an energy projectile that can cut through anything in it's path. The attack was later adapted by other fighters and who were able to control the Kien:Zan making it even deadlier. This attack is also known as the "Destructo Disc."
Ki:Ko:Ho:Tien's most powerful attack, the Ki:Ko:Ho is a powerful energy projectile that can be performed after excessive charging. This attack is also very dangerous to the user as after excessive use, it will kill the user.
Light Speed*:Used by almost everybody, the person using it is able to move so quickly that they can no longer be seen even if they are right in front of a person. The only way they can be seen or even heard is by intense concentration or by going Light Speed with the person.
Makankosappo:Possibly Piccolo's most powerful attack, the Makankosappo is an energy blast that consists of a straight beam and another spiraling beam around the straight one for more power. Cell can also perform this attack with only seconds of charging, while Piccolo must take minutes. This attack is also known as the Cannon Beam.
Masenko:Gohan's signature move, the Masenko is a strong energy projectile that takes little time to charge.
Mind Freeze*:Used by Godo, this attack freezes the opponents in place so that they may not move under any circumstances unless the user is distracted.
Renzoku Energy Dan:By moving one's arms quickly, this allows the person to shoot multiple energy projectiles at a time. This can cause serious damage when used in an amount of hundreds or thousands.
Shin:Ki:Ko:Ho:Tien's improved version of the Ki:Ko:Ho, the Shin:Ki:Ko:Ho is not as deadly (to the user) and is more powerful.
Shinshin:No:Ken:One of Tien's signature moves, the Shinshin:No:Ken creates multiple clones of Tien, but each clone has only a fraction of the original strength. Cell can also use this attack, however, Cell's clones are approximately the same strength as when he was one.
Shiyoken:Used by Tien in the Dragon Ball series, the Shiyoken is the ability for Tien to grow more arms so that he ends up with four arms allowing him to attack better.
Shunkanido:Used by Gokou and Cell, by placing two fingers upon one's forehead, they are able to instantaneously teleport to another location. However, one can only teleport to a place with a person or being with ki and not just any barren desert. This ability is also known as Teleportation.
Solar Flare*:See "Taiyoken"
Souki:Dan:Used by Yaumcha, the Souki:Dan is an energy projectile that can be controlled so that it follows the opponent.
Spirit Bomb*:See "Genki:Dama"
Taiyoken:Developed by Tien but used by many, the Taiyoken is an attack where the sun's light is reflected and magnified off the user's hands. This causes intensely bright light to come from the person's face and hands thus blinding the opponent looking at him. This attack is also known as the Solar Flare.
Teleportation*:See "Shunkanido"
Time Freeze*:Godo's signature move, the Time Freeze allows the user to temporarily freeze time, stopping objects even in midair. However, when the move is performed, one's breath must be held and if exhaled then time starts again.
Triform*:Used rarely, the Triform splits a person into three persons much like the Shinshin No Ken. Though the person's attack level goes down, this technique is quite effective if used correctly.
Zanzoken:The ability to move so fast that the person leaves their image at a location while he is really elsewhere.