Song of Magic

Bardic song
Daily
Action: 
Quick action each turn; 16+ to sustain
Opening & Sustained Effect: 

Until the start of your next turn, you and your nearby allies who cast spells that are normally expended by being cast can roll a d20 after casting the spell. On a 16+, the spell is not expended.

Final Verse: 

All spells you and your allies cast before the start of your next turn gain a +2 attack bonus.

7th Level Spell: 
Gain a bonus to song of magic's sustain check equal to the escalation die.
9th Level Spell: 
Rolls to retain expended spells gain a bonus equal to the escalation die.