Synergies

Rising Tempo
Rising tempo (gold) + Quickstrike (common) slotted with Bronze boomerang (rare gem)

Theoretically infinite damage, although inconsistent : sometimes the draw happens before the reshuffling (might be a bug). You can work around it by having a stack of daggers to redraw quickstrike if needed, or slotting it with a copy gem like Mirror moonstone. Against the greed boss, an energy card with bronze boomerang will be needed to keep comboing. Against the dissolve boss, this just won't work.

Put back on top
Aurora has a few ways to put a card from your hand on top of your library : Fateweave, Seer, Foresight, Split the timeline

This is useful on its own, but also combos with "whenever you draw this card" effects like Rain of fish, Phantasmal might and Crystallized faeria (gem)

Dissolve
Sharra has the ability to dissolve a lot of cards for no mana, with cards like Fan of knives and dagger talents. Aurora herself can stack a few Sips and unloading daggers is a good way to enable their Combo.

Aurora has multiple ways to take advantage of that, with cards like Disciple or Aurora's dream, and her Kappa strength talent combined with multi-hit attacks like Hailstorm.

Cards in hand
Aurora has a few cards with an effect that counts cards in hands. This accounts for all the Stacks cards, so a stack of daggers will significantly increase your hand size. With cards like Fan of knives + the Knife juggling talent, they can go completely nuts.

Power
Both heroes can benefit from additional power, and both are pretty good at giving some.