YaSLP-GUI is a very user-friendly graphical interface which will only show you servers which are online. You don't need to search for a server list. The GUI has 2 built-in server list databases which are ready to use. We are two guys who are yet to learn more about how to code in C#, so there could be bugs in there.
FAQ:
Q: How do I use the GUI? A: Download the GUI select a path where the lan-play-client from Spacemeowx2 (https://github.com/spacemeowx2/switch-lan-play) should be located. Install Winpcap or Npcap with Winpcap Compatibly enabled. Have Fun.
Q: What's different to other GUIs? A: Pretty simple! We use the GreatWizard Database, the server list from https://github.com/GreatWizard/lan-play-status, and R3n3.at, which is our own database which is not finished yet but is fully functional and can be found at http://slp.r3n3.at/.
Q: Can server hosts add their servers to the R3n3.at database? A: Sure! Its pretty simple. Go to http://slp.r3n3.at/ and press the "New Server Entry" button.
Q: Why did you make a second server list? A: Not everyone is familiar with GitHub so we made a new list which is also user-friendly.
Q: Why do you not want to show online servers? A: Kutaro wanted it this way because as the server list grows it would be very difficult to find online servers.