Any metamagic feats to increase one's caster level?

[Endarire]

I was hoping to use my Incantatrix abilities to boost the CL for an allied Druid's venomfire.

[littha]

Heighten spell when combined with Earth Spell.

[darqueseid]

metamagic school focus doesn't have the heighten limitation so you can technically heighten a spell to 1 above your level, then apply earth spell to it too

[sirpercival]

One thing to note about Earth Spell is that RAW it only increases CL based on the slot you cast the spell out of, not the effective level of the spell.  Annoying for my super-CL ScM...

[darqueseid]

But it still stacks with metamagic heighten for effective spell level right? Not for CL but ESL yes.  Meaning you can get an effective spell +2 levels so you can mimic a spell at + 1 spell level.

Example a scm can use a earth spelled mmsf silent image to cast an effective 7th level spell slot which gains a level from earth spell and an increase in CL of +6 (meaning he can mimic a spell of 7th level or lower with a 6th level slot 3 times a day at 11th level).

[sirpercival]

Yes, it still works for effective spell level.  It's just not as big a boost if you don't cast it out of a high slot (by using MM reducers).