While Yoko and J are stuck in the Edo period, Yoko is panicking on what to do while J is rather indifferent on the issue. As Yoko and J are disguised, J is taking note of the surroundings with a magnifying glass while Yoko is dragging him around.
Shortly after, Yoko and J run into Gai, who immediately begins to do his usual geeking out over meeting a new Sentai team, only to realize mid-geeking that he's actually the most experienced member of the team. He pauses to consider that, at which point Yoko yells at him that none of that is important right now. Gai actually glares at her and calls her a "whippersnapper".
Poor Gorisaki being chased by a T-Rex.
Hiromu's reaction when Marvelous says he's eating chicken curry when they meet outside of battle for the first time.
Made even funnier by Yatsudenwani confirming it in the background.
When Usada makes it to the Edo period, Yoko and Gai are happy to see him, while J notes that the rescue was late.
J interrupting Jin mid-speech about how J will be Enter's opponent, and Jin fuming about it soon afterward.
The Kyoryugers' Early-Bird Cameo, when Red makes his big entrance, he realizes that he's the only member of his team present. Even better after you've seen some Kyoryuger - the team isn't much of a team at the beginning and so the first Kyoryuger to find out about the problem of the week - usually Daigo - often ends up asking the others what took them so long to show up.
The reference to Magiranger when Masato did the Magiranger hand pose.
It's funnier if you know the fact Tsubasa's actor also played Masato during Go-Busters. That's why during the Megazord Keys sequence, Masato finds himself in Magi King and says "this feels sorta familiar" or some such.
The various scenes during the end credits.
While the 4 other Go-Busters are talking to the 3 Buddyroids, J is found walking away faster than usual, Jin calling out for him.