Bolt extension to add gravatar twig helper.
Easily add the "Cookie Consent" script from Silktide. A free solution to the EU Cookie Law. Based on https://silktide.com/tools/cookie-consent/ No JS framework requirements, custom labels, several available templates or feel free to create yours.
This Bolt extension makes easier to display OpenAgenda events on your website (OpenAgenda: Get an efficient public calendar now). This extension uses also external CalendR PHP lib, to manage calendar view and load json OpenAgenda events on it.
Bolt extension to send email when new content is published. Foreach ContentTypes, configure if email notification should be send, to which persons, and format each email template. Nice to notify blog followers of new entries or whatever you add to your website.