Agnimitra & Viviane both only have a default set each, both of which are a bit middling and fire based. A fair few of our customer base ie those for whom violence is the answer tend to be somewhat fire resistant. It means the lasses miss out on adventuring and get stuck home.
Agni is probably the harder of the two, but you could lean into the resurrection side of phoenixes and go heavy healer or go other mythic birds like a thunder-hawk [I can't think of any other companions with an electric set].
Vi is much easier she talks about trying out different personas previously [witch's hat / magi-cock] . At the very least she should get access to a new set if you turn her into a demon, possibly as the result of a "Well you're a demon now" chat with Kas or any of your pet demons.
As for more regular sets the WiKi lists her occupation as Witch / Mage / Enchantress that's two additional sets there.
I hope this is taken as constructive criticism.