All footage of Darkonda and Red Ranger fighting as shown in what appears to be Andros' dream is Sentai footage. This footage comes from Mega 20.
Here's new footage of the Key Cards.

Please click on the shot of the planet Onyx down below in order to view a collection of pictures of a shot of Background Monsters from this epiosde.

Here's an exterior shot of Onyx.
All Onyx-related stuff is new footage.

Footage of Darkonda as shown on the Megaship's Viewing Screen which 1 of the shots is shown here is all new footage.
After the Megaship scene with the 5 Rangers and Alpha 6 in it, as soon as you see the following shot of the morphed Red Ranger, it's the start of the Sentai footage.
This shot of Darkonda is still Sentai footage.
This shot of Darkonda is when the new footage begins.
All footage of Ecliptor is new footage even though he's talking to Darkonda while Darkonda is in all Sentai footage.
The foottage of Darkonda growing and then appearing in a Giant mutated form is all Sentai footage.
This shot of the Rangers is when the new footage starts back up.
All following shots of the 5 Rangers on the ground is new footage while all shots of the mutated Giant Darkonda is Sentai footage.
The shot of the Rangers calling for Astro Megazord power is new footage.
Here's Ecliptor and Astronema.
Some of the footage that the episode ends on is actually from Mega 32 due to the fact the Astro Delta Megazord continues on its back for a lot longer than it did in Mega 31.
All Giant footage is Sentai footage which includes all shots of mutated Giant Darkonda as well as all shots of the creature that spawned off of Darkonda which is known to be called Mutantrum.

Following info comes from Mega 31.
Here's a shot of the 5 Rangers along with being in the same shot as Darkonda's hand.
Here's a shot of Giant Darkonda but this Darkonda I'm referring to as "Mad Darkonda."
Here's a shot of the Astro Delta Megazord's Fiery move hitting "Mad Darkonda."
Here's Giant Mutantrus and Giant "Mad" Darkonda.
Here's a shot of Giant Mutantrus.