Shameless self promotion: I build a logo search engine that currently has almost 500K logos indexed: https://logosear.ch/
Also, a good source of official SVG logos is BIMI, a standard that uses DNS to point to the URL of an SVG.
Spec: https://bimigroup.org/
I recently scraped them for the top N domains: https://bimi-explorer.svg.zone/bimi/