Basic Shodan Filters - Credits to humblelad

city:
Find devices in a particular city.
city:"Bangalore"

country:
Find devices in a particular country.
country:"IN"

geo:
Find devices by giving geographical coordinates.
geo:"56.913055,118.250862"

hostname:
Find devices matching the hostname.
server: "gws" hostname:"google"

net:
Find devices based on an IP address or /x CIDR.
net:210.214.0.0/16

os:
Find devices based on operating system.
os:"windows 7"

port:
Find devices based on open ports.
proftpd port:21

before/after:
Find devices before or after between a given time.
apache after:22/02/2009 before:14/3/2010

Citrix:
Find Citrix Gateway.
title:"citrix gateway"

Wifi Passwords:
Helps to find the cleartext wifi passwords in Shodan.
html:"def_wirelesspassword"

Surveillance Cams:
With username:admin and password: :P
NETSurveillance uc-httpd

Fuel Pumps connected to internet:
No auth required to access CLI terminal.
"privileged command" GET

Windows RDP Password:
But may contain secondary windows auth
"\x03\x00\x00\x0b\x06\xd0\x00\x00\x124\x00"

Mongo DB servers:
It may give info about mongo db servers and dashboard
"MongoDB Server Information" port:27017 -authentication

FTP servers allowing anonymous access:
Complete Anon access
"220" "230 Login successful." port:21

Jenkins:
Jenkins Unrestricted Dashboard
x-jenkins 200

Hacked routers:
Routers which got compromised
hacked-router-help-sos

Open ATM:
May allow for ATM Access availability
NCR Port:"161"

Telnet Access:
NO password required for telnet access.
port:23 console gateway

Misconfigured Wordpress Sites:
The wp-config.php if accessed can give out the database credentials.
http.html:"* The wp-config.php creation script uses this file"

Hiring:
Find sites hiring.
"X-Recruiting:"

Android Root Bridge:
Find android root bridges with port 5555.
"Android Debug Bridge" "Device" port:5555

Etherium Miners:
Shows the miners running ETH.
"ETH - Total speed"

Tesla Powerpack charging Status:
Helps to find the charging status of tesla powerpack.
http.title:"Tesla PowerPack System" http.component:"d3" -ga3ca4f2