For Aqua and Ventus, Time Splicer is pretty much a combo, there. With Ventus I could use just that command and get into Wingblade after a bunch of combos. For Aqua, it gets her Gauge up enough to use whatever finisher I have equipped (Usually Heal Strike/Curaga Blade). With Terra, Sonic Blade is my favorite command. As for complex combos with commands, I think the farthest I have gone is Zero Graviga and an onslaught of standard attacks. Or does Firewheel spam>FireStorm mode>Bladecharge in about a minute count? I love doing that with Aqua...
