Mahayana texts, for example. They belong to a later period, and some of them portray the Buddha with cosmic powers far beyond what the early texts describe.
If there are Pali texts that speak of the Buddha’s omniscience on such an extraordinary scale, I can’t recall any at the moment.
Anyway, a strong theist would probably consider this kind of omniscience inferior when compared to the omniscience of God.
Try Sabbaññutā.
These threads discuss the omniscience of the Buddhas: