Forever Red - S1-E34
Corrected entry: This episode features a reunion of ten past and present Red Rangers from the different Power Rangers series. At the climax of the episode, all ten rangers morph. However, this should be impossible, as several of the ranger powers had either ceased to exist (as in the case of the Lost Galaxy powers) or been given up by their previous holders (such as Jason, who ceded the original Mighty Morphin' powers to Rocky).
Correction: The Lost Galaxy powers are still around, just dormant inside the Quesar Sabers. As for Jason, his Power Coin was dupilicated using the Sword of Light, hence why there are two Red, Black, and Yellow Rangers during "The Power Transfer (2)." Since Jason was not in the battle with Rito in "Ninja Quest (1)," his Coin was still active. Or, if you choose, it healed itself (much like Adam's coin started doing in between "Ninja Quest (1)" and "Always a Chance"). As for T.J.'s powers, they were restored once the attack on Eltar stopped, since Justin was able to become a Turbo Ranger later on.