When new features make their way into standard WordPress, more often than not their functionality has started off as a plugin. Plugins that get on the roadmap to being integrated are proposed and put forward for active development, in preparation for their integration into the core release.
You can contribute to this process simply by installing one of these plugins and giving them a good old test run. By doing this, you’re helping, flagging any issues you come across by subjecting the plugin to actual real world usage.
Head to wordpress.org/plugins/browse/beta to see which plugins are currently on the roadmap to being include in the core WordPress release.
As always, do let us know what you think of this plugin, or if you’ve got a plugin you can’t go without when developing in WordPress make sure you give us the heads up.