I can't think of anything with more Strength than that. If you want to get technical, there are a few monsters that advance size as they gain hit die that would reach a STR of 50 or higher from those size bonuses (The Blackstone Gigant out of the Fiend Folio and the Goristro out of Fiendish Codex I, for example) and that technically fits your non-templated, first-party, non-unique, non-epic requirement, but I'm not sure if you're looking for something that involved. I think if you're looking for a creature with the highest all-around stats, you'll be hard-pressed to beat the Dragons.