In Masters of the Wild, there was a spell called adrenaline surge. It is worth a look for summoners.
In addition, many DMs have adopted a house rule regarding spell focus:
When selecting spell focus, you may select one of the following options:
1.) Gain a +1 to the DC of spells you cast from this school,
2.) Gain 1 bonus spell per day of the highest level spells you can cast. This may only be used to memorize a spell from this school, or
3.) Increase your caster level for all spells from this school by 1 level.
Adopting this house rule makes spell focus useful for all schools of magic, not just evocation, enchantment, necromancy and transmutation.