Welcome to another quick article! I will be showing you some Shodan search commands you can use. I have not found a list online and figured I'd make one for this purpose. I will be adding to this list over time.

Before we dive into this, remember: make sure you’re wearing your white hat before walking out into the cyber security world. Shodan is meant to be used as a research tool. Manipulating any unauthorized system is illegal. If you do not know what Shodan is or how to use it..... you probability need to leave this site.

Shodan Cheat Sheet

Here are the basic search filters you can use:
city: find devices in a particular city
country: find devices in a particular country
geo: you can pass it coordinates
hostname: find values that match the hostname
net: search based on an IP or /x CIDR
os: search based on operating system
port: find particular ports that are open
before/after: find results within a timeframe

Examples
Find Apache servers in San Francisco:
apache city:"San Francisco"
Find Nginx servers in Germany:
nginx country:"DE"
Find GWS (Google Web Server) servers:
"Server: gws" hostname:"google"
Find Cisco devices on a particular subnet:
cisco net:"216.219.143.0/24"

Search Commands: Search the commands in between the brackets [typethisintosearchbar]

[port:30718 lantronix password -secured] --Recent thousands of serial to ethernet devices leak telnet passwords (12.2.17)
[port:3389]--Windows RDP
[vsftpd 2.3.4] --description says has easy root backdoor
[device:printer port:23]
[ATM Networks port:"10001"]
["iss/5.0"]
["iss/4.0"]
["iss/3.0"]
["iss/2.0"]
["iss/1.0"]
[Microsoft-IIS/4.0 title:"outlook web"]
[netgear port:80]
[Anonymous access granted] --mostly ftp servers
[shellshock]
[heartbleed]
[Loxone]

https://hackertarget.com/attacking-wordpress/
[wordpress]
[WordPress 3.0]
[WordPress 3.5.2]
[struts]

https://hack-ed.net/2016/02/01/tango-down-shodans-full-potential/
https://pen-testing.sans.org/blog/2015/12/08/effective-shodan-searches
https://hack-ed.net/2016/01/30/shodan-the-internet-of-things-search-engine/

Enjoy!