U.S. DNI Worldwide Threat Assessment 2019 

ActorTrackr

Alerts @ US-CERT

Alerts on ICS @ ICS-CERT

Apility.io

APT Groups and Ops

ASNs w/ Malicious Activity

AutoShun

BGP Ranking (from circl.lu)

C1fApp

C2 IP addrs (from John Bambenek)

Check Point's ThreatCloud

Critical Stack Intel

Cyber Threat Alliance (CTA)

CyBot threat intel chat bot

Cymon by eSentire

Deepviz Threat Intel

DHS AIS

DNS Trails (historical archive)

Dragos' Bob Lee on CTI

Emerging Threats Firewall Rules

Emerging Threats IDS Rules

ExploitAlert Statistics

Facebook ThreatExchange

FireHOL IP Lists

Google APT Search Engine

Grey Noise (scanners)

Hail a TAXII

I-Blocklist

IBM X-Force Exchange

Intel Threat Dashboard

IntelMQ threat intel consolidation platform

MalwareDomains.com

Malware Domain List

McAfee Threat Activity

Metadefender.com

MineMeld threat intel platform

Minotaur (threat research)

MIPS threat sharing platform

UK National Cyber Security Centre (NCSC)

NetLab OpenData Project

NormShield

OpenIOC threat sharing framework from FireEye

OpenPhish Feeds

OTX - Open Threat Exchange from AlienVault

PhishTank

PulseDive threat intel platform

SANS Internet Storm Center

SANS Suspicious Domains

Sotra Edge (basic)

Spamhaus

STAXX from Anomali

Strongarm by Percipient

Symantec Security Response

Threat Hunting Academy

ThreatCrowd

ThreatExchange (by Facebook)

ThreatMiner

TOR Relay Lookup

TrendMicro's Threat Encyclopedia

VirusShare

X-Force Exchange (by IBM)

Yara-Rules

Akamai's Global Client Reputation

Arbor Networks Digital Attack Map

Blueliv Threat eXchange

C1fApp Threat Map

Check Point's Cyber Threat Map

Deteque Botnet Map

FireEye Cyber Threat Map

Fortiguard's Cyber Threat Map

Grey Noise (maps of scanners)

Google/Arbor Digital Attack Map

HTTPCS Cyber Attack Map

IBM X-Force Exchange

Kaspersky Cyberthreat Map

LookingGlass Threat Map

Malwaretech's Intel Map(s)

Norse's Cyber Threat Map

Pixalate Cyber Threat Map

Security Wizardry CTI Board

Shodan ICS Radar

Shodan Maps

Shodan 2000

Skycure Threat Map

Threatbutt Attack Map

ThreatExpert Map

ThreatMetrix CyberCrime Threat Map

TrendMicro's Botnet Map

TrendMicro's Spam Map

World's Biggest Data Breaches