There are 3 abilities which can target allies and use projectiles:

1. Abaddon's Mist Coil
2. Oracle's Fortune's End
3. Ethereal Blade's Ether Blast

These projectiles are also disjointable. Meaning when cast on allies, they can disjoint it as well.

Disjointing should probably be only a beneficial move done to dodge enemy spells, and not allied spells. Like, an ally will never attempt to dodge your spell intentionally. They will also not think of the possibility of it happening. So as of now, as Abaddon or Oracle, you have to wait for your ally to use their blink before you can heal them or dispel them, or protect them with e-blade. It can get frustrating sometimes.