Fierce - https://github.com/mschwager/fierce
Subli3ster - https://github.com/aboul3la/Sublist3r
EyeWitness - https://github.com/ChrisTruncer/EyeWitness
dnssearch - https://github.com/evilsocket/dnssearch
Altdns - https://github.com/infosec-au/altdns
Brute force subdomain list