We have 3.3 million year old stone tools https://www.nature.com/articles/nature14464. They're very simple (even more so than the Oldowan stone tools https://en.wikipedia.org/wiki/Oldowan) and basically just look like rocks, but there is clear evidence of intentional shaping by hominins (somewhere in the fuzzy late Australopthis/early homo transition).
Thanks for these sources. Archeology definitely is a big known unknown for me, so even getting started reading basic info about this is rough. I appreciate the links and terms.