What interesting things can I do with my home WiFi network?

I recently learned about LocalSend and was intrigued by how it functioned by only using the WiFi network of the devices. I did not know my LAN had these capabilities.

Now that I've learned about it, I am excited to know if there is anything else I can do with it. Perhaps there could be a way to send prank notifications to all the connected devices, create a private chat room, or have custom LAN parties.

I genuinely do not know anything about how WiFi or LAN in general works in this matter. Is it possible for me to build my own applications that make use of these features? If so, I would love to get a direction on what resources or guides I should be looking for. If not, I would still be happy to use similar pre-built applications.