A plain ole' react-big-calendar.
npm i then npm run start - it'll open in your browser, localhost:3000
clickin' on a day creates an event for that whole day, click and draggin on multiple days creates a multi-day event. if you go to the top right corner, you can view it from a month, week, day, or schedule view and choose a time slot to create an event.
this is built off of react-big-calendar and the starter kit react-big-calendar-starter