It hasn't happened a lot but sometimes there is a trend to have a hint to the theme of the next following Sentai theme in the Super Sentai. I am not talking about future Sentai series, but one after another.
I was reminded that Ryta of Jetman (1991) was sent to the past by a Mammoth monster to prehistoric times, which was used the exact next year for Zyuranger (1992). In the above picture, he met a cavegirl that liked him. He was Yellow Owl.
In Gaoranger (2001), they fought a Ninja who had his own shadow rangers to fight the heroes, many feel this was Toei testing out the ninja work for Hurricanger (2002), which follow afterwards. This footage was used for Power Rangers and had the same feeling.
In Go-Onger (2008), they often got visitors from the Samurai World and the movie exclusively featured the Samurai World. Three Engines formed the Dai Shogun, which was like a samurai. This theme was used in the next, Shinkenger (2009). Dai Shogun footage was not used for RPM. funny enough PRWF and PRNS were transfer of Disney to Saban and RPM and PRS are once again transfer of ownership.
In Goseiger (2010), the Seaick Gosei Great has a pirate look, and now the new theme in 2011 is Gokaiger. Funny enough, both series were used for Megaforce (2013-2014) and while the pirate theme isn't being referenced on the show, we see Sea Gosei Great Megazord during the second season Super Megaforce that uses mostly Gokaiger footage.