IC part numbers. Service manuals (NOT user manuals). Schematics. Basically anything repair or non-consumer-oriented seems to be difficult to find, but at least in the past, I've had some success with Bing on those things.

Is hellbanning a thing at Google? What happens if one gets hellbanned?

You get redirected to a page with allegations of "suspicious activity" and are presented with endless CAPTCHAs.