Fiendish Summoning Specialist

Prerequisite(s): Knowledge (the planes) 2+ ranks, Knowledge (religion) 2+ ranks, ability to cast any summon monster spell, Nongood alignment.
Benefit: Add one evil-aligned creature to the list of creatures for each summon monster spell that you can cast. (Work with the DM to select creatures appropriate to the spell's list of summonable creatures.) Each time you gain the ability to cast a new summon monster spell, you may add one evil-aligned creature to the list.
Source: Planar Handbook