[Den-O]

They may not be exactly the same story wise either but I feel like they're good quick intros to past series. It helped me choose what show to watch after I finished Decade and had a years worth of time to kill before the Decade/W movie came out. I reccomend it for that and if nothing else just the pure absurdity of one rider turning into a bunch of others as well as turning a bunch of other riders into comicly awesome weapons.