Movie, TV, book or video game spinoffs you wish existed.
I'm still disappointed we didn't get that Rupert Giles or Faith spinoff from Buffy the Vampire Slayer. I remember when it was rumored to have been in the talks way back when, and I was super excited because the Giles spinoff was going to be called Ripper and it was supposedly going to explore his backstory a bit. And having a Faith spinoff was simply because of her character being so well beloved by fans, and it would've been a nice way of looking at her character. I also liked the notion that Eliza had about Faith traveling on a motorcycle. But alas, these things didn't take.
Back when I was part of the fandom I wanted Supernatural to have a spinoff focusing on the angels, centering around either the war between angels and demons or the civil war in Heaven (or both) since they kind of wasted so much potential and opportunity on the actual show with all of that mythology.
I also wanted more storytelling within the Battlestar Galactica universe. We already had the prequels Caprica and Blood & Chrome telling what happened before and during the First Cylon War, but neither of them survived long enough to further tell their stories. If there was to be another spinoff from that universe, as unlikely as it seems at this point, I would've wanted something centering around like the Final Five and the Thirteenth Tribe or what Kobol was like before, and really just more exploration of the things that were alluded to in the series but never really got much answers to or to just simply see how things were to expand the story.
Also, as a general observation, spinoffs seem to become more common these days than before some years ago. So many shows have announced that there's a spinoff in the works. I don't know, I find it interesting.