EonEye99, sorry for responding to you so late!
As for Regigigas, it basically revolved around one key card,
Regigigas LV.X. Its main forte is its absolutely titanic HP, combined with a Poke-Power that, although it gives your opponent a prize, keeps him alive perpetually. The three Pixies from LA (
Uxie,
Mesprit,
Azelf) were used in the deck not only for their effects, but also to serve as Sacrifice fodder. Mesprit's exceptionally noteworthy for its power-lock effect, and due to Sacrifice, bench space is not an issue with any pixie.
Gigas would use either
Recover Mechanism or
Drag Off Gigas as a base, depending on style of play (the former for just sheer power and a bit of sniping, the latter for disruption). After that, you can pretty much add whatever techs you feel help the deck the best. The most crucial ones were the three pixies, and later on,
Expert Belt and then
Twins and
Black Belt - all of which exploit the prize exchange very well. (With an Expert Belt plus
Snowpoint Temple in play, Gigas X can reach a staggering 190 HP!)
Regice is also noteworthy as it can actually set up a T2 Giga Blaster. (Discard 2 energy for its power, use Sacrifice to attach them to Gigas, and by then Gigas should have 2 energy on him already, so fire away.)
I'd call mine RegiAwesome/Crazy Gigas/Gigasbox because it was built to adapt to any situation, and Gigas was not the deck's only attacker. There are a thousand ways to play Gigas, and the best way to go was to play it in response to the meta around you.