The best replacement for instax is instax mini.

The best alternatives to instax are rated as following:
★★★★★  instax mini
★★★★  polaroid 300
★★★★  polaroid
★★★  polaroid 600
★★★  polaroid z2300
★★★  impossible project
★★  zink
★★  lomo
★★  pogo
★  polaroid better
  polaroid pogo

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

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



Google Trends

Scale is based on the average worldwide traffic of instax in all years. Click on graph for more.
instax
instax mini
polaroid 300