Tools
These are some tools I like along with some example usage
Censys
A massive query capable database of ongoing Internet scans. For example, here's the query I used to find Certificate Authorities which issue valid TLS\SSL certificates to IP addresses
443.https.tls.validation.browser_trusted: true and 443.https.tls.certificate.parsed.extensions.subject_alt_name.ip_addresses: [0.0.0.0 TO 255.255.255.255]
CyberChef
The ultimate swiss-army knife of encoding/decoding strings.