FullCalendar - FullCalendar is an open-source JavaScript event calendar.
Charitable - A WordPress donation plugin that gives you full control over your fundraising experience.
Dudle - Dudle is an online scheduling application, which is free and open source.
Give - A WordPress plugin for easily collecting donations
Mobile-Calendar - Reservation management system. If you rent accommodation, the mobile-calendar app was made for you!
FreeFunder - Free crowdfunding platform with no platform fee and donates to your fundraiser based on shares!