The linked image search result for "AI" actually consists primarily of brain-shaped circuit boards which, y'know, is actually not a terrible metaphor for artificial intelligence.

Personally, I'm kind of partial to Google's Cloud AI logo [2], but I work here (Cloud, not AI) so I may be biased.

[1] https://medium.com/@ageitgey/the-real-scandal-of-ai-awful- stock-photos-456633b9b0fc

[2] https://cloud.google.com/products/machine-learning/