We have our own search crawlers that work 24/7. As such, we use data from our independent database and are not affiliated with other search engines or similar services (we do not use data from Alexa, Altavista, Google, Webalta, etc.).
We are proud to have the largest index of live backlinks that gets updated every 15 minutes.
Cloudflare Radar mentions AhrefsBot as #6 in its list of "Verified" good bots. Their list is ordered by the number of requests made, which shows that we're one of the fastest crawlers on the web.
We have lots of historical clickstream data, which is still blended into our data to a certain degree. We also use GKP data, GSC data, and some other sources that we mix together to populate our keyword database and refine our monthly search volume numbers.