nodebb-plugin-iframely(latest: 0.7.14) Iframely will give you embeds from over 1700 domains, plus previews for the rest of the web.
nodebb-plugin-tarsnap(latest: 1.2.8) This is a Tarsnap plugin for NodeBB. Keep in mind it is merely an interface, and **you still have to figure out how to install Tarsnap on your server** before this plugin is of any use.
nodebb-plugin-blacklist-country(latest: 1.1.3) This plugin allows administrators to ban entire countries from registering and logging in. Please be aware that this is a heavy-handed approach and should not be used lightly (or temporarily)!
nodebb-plugin-audio-embed(latest: 1.1.7) This plugin allows users to upload audio files (mp3 files, specifically) and embed them into posts.
nodebb-plugin-mentions(latest: 2.13.6) NodeBB Plugin that allows users to mention other users by prepending an '@' sign to their username
nodebb-plugin-knowledge-base(latest: 1.1.0) This plugin exposes a new category-level privilege called "Knowledge Base". When enabled for a specific category, all top level posts in that category will become editable by other users.
nodebb-plugin-2factor(latest: 2.9.1) In addition to regular authentication via username/password or SSO, a second layer of security can be configured, permitting access only if a time-based one-time password is supplied, typically generated/stored on a mobile device.