Super Sentai Series With Post-Series Specials
There were some Super Sentai that can be noted for having post-series specials. These are the following:
Chojin Sentai Jetman- After the conclusion of 51 episodes, there came out the Jetman Toei Hero Encyclopedia where Ryu and Kaori are featured as a married couple, they talk about their days as Jetmen before living normal civilian lives. Along the way, they recall their adventures and in the end, it's discovered they have named their son as Gai, named after their late friend Gai Yuki.
Mirai Sentai Timeranger- After the tearful bittersweet conclusion of Timeranger (since Tatsuya and Yuri well it's impossible for them to be together), we do get a special which is a self-contained episode. The first five Timerangers go use the Time Gamma to see all the Super Sentai series as the years passed from Goranger down to Gogo V before it ends with the endorsing Gaoranger which became the anniversary special (25th season).
Samurai Sentai Shinkenger- There was the Shinkenger Returns OVA but I really didn't like it for being too messy.
Tensou Sentai Goseiger- It had an OVA after the series ended. Hmmm and they became international figures. I am yet to see it.