I simply write plugins for Minecraft servers for free. As soon as a cool idea pops into my head, I just go ahead and implement it, then share the open-source code online.
If you liked my idea and would like to see it developed further, simply leave a review on SpigotMC, GitHub, or similar platforms.
If you would like to contribute to the development, start by making a useful contribution via a Pull Request—for instance, by addressing user requests from the Discord server. Once you have done so, you can become a full-fledged member of the project.