There are many working Wi-Fi finders with positive reviews from users. Examples include Wi-Fi Analyzer for Android and Wi-Fi Finder for Apple iOS. For Windows laptops, there are utilities such as InSSIDer. Mac OSX has a native Wi-Fi diagnostics app. Similar software is also available for Linux.
The effectiveness of any Wi-Fi finder software ultimately depends on the specifications and real-world performance of the wireless networking technology it is used with. If a wireless card cannot pick up any trace of a nearby Wi-Fi hotspot signal, no Wi-Fi finder software can locate it. In practice, most devices work well with Wi-Fi network detection programs that are simple to use and designed for the novice user.