Board Thread:General Discussion/@comment-31252171-20171002090018/@comment-13682699-20171009034905

Flowey probably has the most knowledge in general about the underground and is considered very cunning.

Sans probably has the best practical knowledge, especially about quantum physics. His natural perception grants him better insight than most.

Asgore/Toriel/Gerson have the most experience with life being the oldest monsters to date, and such experiences mean greater knowledge about the world in general. (Though Toriel undoubtedly has the greatest smarts amongst the trio and is considered particularly witty)