Abilities that work with Dragonsong?

[Zombimode]

Dragonsong (Draconomicon) increases that save DCs of all abilities that are based on poetry or song by +2.

Now, thats a cool feat, but is begs the question: which feats or class features could actually benefit from that?

Greater Dragonsong of the Dragonsong Lyrist PRC for which this feat is a prerequisite, and some uses for bardic music are a given. Is there anything else?

[Piggy Knowles]

Expanded uses of bardic music found in other prestige classes should still qualify. For example, the Stormsinger's stormsongs should be boosted by this, as should the Warchanter's inspire awe.

Can't think of much beyond that, though...