AbuseIPDB
IP/domain/URL reputation
Anti-Malware
AlienVault Open Threat Exchange (OTX)
IP/domain/URL reputation
CAPEsandbox
Malware execution and analysis
Google Safe Browsing
Google Link/Domain Flagging
MalDatabase
Provide malware datasets and threat intelligence feeds
MalShare
Malware Archive / file sourcing
MalwareBazaar
Collect and share malware samples
Metacert
Metacert Link Flagging
NoPhishy
Check links to see if they're known phishing attempts
Phisherman
IP/domain/URL reputation
Scanii
Simple REST API that can scan submitted documents/files for the presence of threats
URLhaus
Bulk queries and Download Malware Samples
URLScan.io
Scan and Analyse URLs
VirusTotal
VirusTotal File/URL Analysis
Web of Trust
IP/domain/URL reputation