The Dawn War Pantheon
The Dawn War Pantheon was founded by Corellon, Pelor, Sehanine, and Nerull, gods of the seasons. No one but the gods know how the Raven Queen defeated Nerull and took his place as God(dess) of Death and Winter, but she was a better alternative to the tyranny of Nerull, and was gladly embraced in the pantheon. The Dawn War pantheon was typically worshipped by humans, but the intermingling of races led to the addition of Melora of the elves, Moradin of the dwarves, and Avandra of the halflings. As civilizations grew, Erathis gained more followers, as did Bahamut and Ioun. And as long as there was battle to be had, Kord has had followers.
The evil gods are not really part of the pantheon, so much as their nemeses. They exist because of the often more desperate faith of their followers.