JustRSVP.me - Online Invitations and response tracking for weddings, baby showers, birthdays, parties, and other...

Attendize Event Ticketing - Attendize is a free & open-source ticket selling and event management platform

RSVPify - A powerful and awesomely customizable platform for selling tickets online for your event.

pretix - pretix helps you to sell tickets for your event in an easy way. It supports multi-lingual events and provides a wide range of features

Evite - Send online invitations for all occasions by email or text message. Create invites for birthdays, baby showers, save the dates, or customize your own design.

Ticket Tribe - Sell tickets online with no fees per ticket