I'm looking for Concept/discarded designs from newer Sentai...

[NeonZ]

Is there anything at all available for those series online?

I've only seen that book with Sentais mecha up to 2002. Isn't there anything newer than that from DVDs or something?

 

[Forever Knight]

I think what u might have seen are the concepts for Zyu2 footage which Saban was going to use from Toei which meant Won Tiger/White Tigerzord combining with Daizyujin/Megazord. Which was eventually scrapped.