Sub Domain Enumeration

Altdns - Altdns is a security tool to discover subdomains by @infosec-au
Amass - We can also find subdomain using Amass by @OWASP
AssetFinder - Find domains and subdomains potentially related to a given domain by @tomnomnom
CRT.sh

Domain - It allows to use the two tool one multiple domains within the same session, combine two tools Recon-ng and altdns by @Jhaddix
SecurityTrails

SubFinder - Subfinder is a subdomain discovery tool that discovers valid subdomains for websites by using passive online sources. @ProjectDiscovery
Sublist3r - Sublist3r is a multi-threaded sub-domain enumeration tool for penetration testers by @aboul3la
Subdomain enumeration Automation - Run this scirpt and find your Subdomain