Finding third-party contact or support information
Developer information for apps on the Mac App Store and App Store can be found on the application's information page.
You can find many companies' contact information via an Internet search engine.
Finding third-party products
If you're looking for third-party software for your iOS device, access the App Store on your device or through iTunes on your computer.
For a list of firewall and security software, see this article.
There are many Wi-Fi router manufacturers. Some popular wireless router manufacturers include: