Any New Relic account can consume, author, and publish plugins.
If you don't have an account, or want to publish from an account that is different from your primary or work account, simply signup for a new account - and if you do so via any of the plugin detail pages here http://www.newrelic.com/platform you'll get New Relic Standard for free, forever! (otherwise Standard is a paid tier, and Lite is free forever)