St. Cuthbert is one of the two oldest gods in D&D history, created alongside Pholtus by Gary Gygax in 1972.
I love the paradox of the name. A god who is a saint. I like the crossover with the real world (mace in a London museum, plus the obvious inspiration from a real-world figure). I dig the sincerity and out-of-place normality of St. Cuthbert. I liked that he never really crossed over into other D&D pantheons. He's a quintessential, syncretic, somewhat incongruent, Gygaxian creation from the early days of the game and triggers warm nostalgic feelings in this old, common-yokel grognard.