Who would you're ideal seterusnya companion be for the 12th Doctor? (It can be a sebelumnya companion)

sebelumnya companions that would be nice: Captain Jack, River, Vastra & Jenny. Maybe Psi & Saibra, atau Shona. atau K-9!!
New companions that would be nice: someone from a different planet, someone not necessarily female atau in their 20's, someone NOT from modern hari London, someone who isn't 'fiesty, flirty and sassy'.