Here's Astronema and Ecliptor along with a Quantron.
All footage of Yellow and Red Rangers on the planet with denser gravity is new footage.
Here's new footage of Red and Yellow Rangers and their Gliders.
All footage from when Andros summoned the Gliders which included when he and Ashley landed on them is new footage as well as the shots of him riding them in outer space.
Here's Astronema.
Here's Elgar and Ecliptor.
Here's new footage of Destructipede.
Buildings coming apart is obviously Sentai footage.
Here's new footage of the Rangers.
Footage of Destructipede as shown on the Dark Fortress View Screen is Sentai footage.
The following shots are all Sentai footage unless otherrwise stated.
Footage of Destructipede growing is Sentai footage but the Satellaser beam was added into the footage.
All following footage is Sentai unless otherwise stated.
In Megaranger, the Delta Mega didn't turn evil, it was just corrupted due to the fact Destructipede could control sound waves or something like that.
First the beam the Megazord was using to try to get the "Delta Megazord" back, in Megaranger, that was just a natural power that the Astro Megazord had.
Secondly - it wasn't stated in Megaranger that the "Astro Megazord" was out of power.
Third - as soon as the Delta Megazord's eyes or "red visor" glowed red, in Megaranger, that's when the Megaranger knew they got it back.
All Giant footage is Sentai.

Following info comes from Mega 21.
Here's Destructipede.
Here's Giant Destructipede.
Here's the Astro Delta Megazord.
Here's a shot of the Astro Delta Megazord facing Destructipede while Fearog tries to grab the Astro Delta Megazord.
Here's a shot of the Astro Delta Megazord after Behemoth attacks it. Sting King can be seen in this shot too.
Here's a shot of the Astro Delta Megazord after Clawhammer attacks it.