LiveCode is very mature, having been around more than 15 years. But for most of that time its license was proprietary only, and the GPL-governed edition has been available less than three years.
So it's easy to find many proprietary apps built with LiveCode, such as these from LiveCode.com's gallery:
https://livecode.com/livecode-stories/
...but not so easy to find open source apps.
There are many libraries, components, and frameworks available under dual-license or GPL only, but completed apps made with the open source Community Edition are often internal productivity tools for use within an organization, and so there are fewer general purpose open source apps in the wild.
We're beginning to see a few, though, and one of my favorites is the Platyvue Project from my friend Matt Maier:
http://forums.livecode.com/viewtopic.php?f=108&t=23852
No doubt we'll see more as LiveCode's open source audience continues to grow, but as with any new entrant in the FOSS world it takes time to build momentum.
What sort of app are you interested in building? I'd be happy to help you find examples, libraries, or tools you may need to help move that along.