[Frontier]

I feel like this movie set up a trend of this kind of "versus" movies that usually just have to contrive a reason for the two sides to fight each other in order to rile things up when fans would probably equally just enjoy seeing their favorite heroes working together and interacting with each other. Which is why I usually prefer the more normal Sentai Versus or Rider x Sentai Versus that happen in the actual shows.

Although if you were going to pair a Rider against a Sentai Red, Decade and Marvelous make a lot of sense. Although I'd probably enjoy a begrudging buddy comedy between these two more than I would them trying to kill each other.

Also look at all the returning in-suit heroes because there was no way we could get that many returning actors back for this! And watch them all die for the sake of the plot until they all show up again...I'm sure that won't become a common thing!