It's RAG via tool use, where the storage and retreival method is an implementation detail.

I'm not a huge fan of the term RAG though because if you squint almost all tool use could be considered RAG.

But if you stick with RAG being a form of "knowledge search" then I think Google search easily fits.

It is tool use with natural language search queries but going down a layer they are searched on a vector DB, very similar to RAG. Essentially Google RankBrain is the very far ancestor to RAG before compute and scaling.