Galactica Donut: A cool looking attack. Gotenks forms a ball on energy in the form of a "donut." The donut goes around the person and squeezes.
Gotenks

Gatai Kousen: Double attack used against Garlic Jr.
Goku and Piccolo

Gekitotsu Ultra Buu Buu Volley Ball: The person is caught in a ball on energy. Gotenks then proceeds to play Volley Ball with the person. Piccolo even plays. The scene is very funny!
Gotenks>

Genki Dama : Or Spirit Bomb. One of Goku’s best, if not the best attack he has. He gathers energy from every living thing on the planet, the trees, people, rocks, water, air (even thought most of that stuff isn’t living.) Everybody donates a tiny bit of energy and it quickly adds up. Goku later learns to extend his energy absorbing abilities far into space. The energy ball formed is very powerful and used only when absolutely necessary. The one against Vegeta was 2 feet wide and the one on Namek was 50 meters wide.
Goku

Giji Super Saiya-jin: A fake Super Saiya-jin. Used in Movie four, it’s not really Super Saiya-jin, and it can’t be called normal either. It’s both, half and half.
Goku

Great Kick Special: Nifty little kick with a funky name.
Gotenks

Guru Guru Gamu: A sticky, gum-like substance that’s shot on the floor. It keeps the person fused in place.
Giran

Gyariku Hou: Also called Garlic Gun. It’s very similar to the Kamehameha. Energy is gathered in the same fashion. The beam is the same as Kamehameha, but it’s purple. Very powerful.
Vegeta