CTI News
Standards
Frameworks
On-line resources
OSINT Tools
OpenCTI
Some informative blogs that range from general threat intelligence to incident response to geopolitical attacks:
DarkReading
SANS Internet Storm Center
The Red Canary Blog
Krebs On Security
Cisco Talos Intelligence Blog
CrowsStrike Blog
CTOvision
DomainTools
Microsoft security intelligence
The DFIR Report
FireEye Threat Research Blogs
The Cybersecurity and Infrastructure Security Agency (CISA)