Web tools :

Censys.io

For finding usernames for in 500+ websites : WhatsMyName

for finding info about a website : DNSdumpster

for Image forensics (ie upload a photo and extract data from it) : exif.tools

Google Dorking :

SUB-DOMAINS :

Google Dorking : go here or do manually by learning

web tools :

Automated-tools : subfinder, assetfinder

use subfinder and this command sudo subfinder -d (domain name) -all > subdomains.txt
after finding all sub-domains we filter the alive ones using httpx

command being cat subdomains.txt | sudo httpx > alive_subdomains.txt

also get to know thier status code by : cat alive_subdomain.txt | sudo httpx -sc > alive_domain_status_code.txt

subfinder -d website.com | httpx -sc -silent

also amass try `amass enum -active -d example.com -brute -min-for-recursive 3