Tatsuya's and Yuuri's feeling for each other. They develop slowly throughout the whole series and it feels really nice.
Also, Domon and Honami, who had a son together.
Episode 35 is full of theese. We have the Timerangers visiting childrem at a hospital. There's a boy who is Naoto's fan, but our aloof Sixth Ranger said he wouldn't go there to see the kid. By the end of the episode, there he is, supporting the boy who's about to undergo surgery and seemed confident after being supported by his idol.