- [Chaos](https://chaos.projectdiscovery.io/#/)
	- Priority #1 - you *must* have this
	- Actively curated and maintained internet assets database
- [Github](https://github.com/settings/tokens)
- [FacebookCT](https://develpers.facebook.com)
	1. Open https://developers.facebook.com and Sign in as a facebook (developer)
	2. Go to apps, create app 
	3. Create app > Your app page
	4. Get apikey
	5. setting > advance setting > security > client token
	6. Get Secret
- [PassiveTotal](https://community.riskiq.com/settings)
- Shodan (not free but very cheap)

- Paid/Limited sources
	- Rapid7 Sonar
	- SecurityTrails - best paid API
	- SpiderFootHX - second best paid API

 - binaryedge
 - builtwith
 - c99
 - censys
 - fullhunt
 - hunterio
 - virustotal
 - zoomeye