The best replacement for invitations is announcements.

The best alternatives to invitations are rated as following:
★★★★★  announcements
★★★  stationary
★★★  save the date
★★  flyers
★★  cards
★★  attendance
★  announcement
★  graduation
★  invites
★  wedding announcements
★  baby shower
  save the dates
  greeting cards
  wedding

Your alternative for invitations is not listed? Suggest!
Speaking about invitations, one probably shouldn't forget about inner envelope.

Other search terms related to invitations and their ratings are:
★★★★★ inner envelope
★★ bling
★★ an inner envelope
You have in mind a companion for invitations and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of invitations in all years. Click on graph for more.
invitations
announcements
stationary