Doctor Who is probably one of the most spin-off friendly shows out there, having embraced the idea for decades. After all, when you've got a veritable swinging door of companions and one-off roles, it's hardly a stretch to come up with characters deserving of their own show. We've seen Torchwood, featuring the exploits of the indomitable Captain Jack; The Sarah Jane Adventures, with one of the show's best-loved companions and her pint-sized team of assistants; even the short lived K9 and Company. But with a wealth of characters, all with their own potential back stories and future adventures, it's hard to resist imagining what it would be like if they got their own shows. Even if that would never in a million years actually happen.
10. Madame Vastra, Jenny, and Strax
These characters are incredibly successful because they seem like they've existed before the episode began and will continue on after it's over. Just because the Doctor isn't around, doesn't mean that they're not off having their own adventures. In a way, they're sort of like a spinoff that just isn't being televised. They create a perfect trinity that works together like a well-oiled machine. Madame Vastra brings the wisdom, Strax brings the comedy, and Jenny brings the much-needed sense of humanity. Their bonds are incredibly strong and believable, even while Strax is grumbling about how he'd rather be off fighting a Doberman or something. And the idea to have this group of ragtag misfits in socially-obsessed Victorian England is a stroke of genius. Also, I'm just going to throw this out there: if they happened to come across Jago and Litefoot in their adventures, I would be OK with that.