Subfinder - Subdomain discovery tool that discovers valid subdomains for websites. Designed as a passive framework to be useful for bug bounties and safe for penetration testing.
github.com/projectdiscovery/subfinder
httpx - Fast and multi-purpose HTTP toolkit allows to run multiple probers using retryablehttp library, it is designed to maintain the result reliability with increased threads.
github.com/projectdiscovery/httpx
naabu - Fast port scanner is written in go with a focus on reliability and simplicity. Designed to be used in combination with other tools for attack surface discovery in bug bounties and pentests.
github.com/projectdiscovery/naabu
dnsx - Fast and multi-purpose DNS toolkit allows running multiple DNS queries of your choice with a list of user-supplied resolvers.
github.com/projectdiscovery/dnsx