Titans, Cloud and Storm Giants. All of these creatures can manipulate weather, help ensure plentiful seasons, and titans can cast arcane AND divine spells as a 20th level caster all before taking a character class! That means polymorphing, healing, resurection, spells right off the bat. I could definately see cults around such creatures, especially among seagoing folk, as the weather control powers available to such beings is considerable.
Maybe an Otyugh scavenger cult with oozemasters being held in high regard. Such a cult could exist within illithid run regions amongst the sewer dwelling drudge-slaves. Maybe they could become immune to the harmful effects of parasites (though still a carrier) , immunity to poison and disease early on, and eventually have their arms become tentacular. A real drawback (though possibly with combat bonusses against creatures with noses)would be their smell!!!