The best replacement for decal is sticker.

The best alternatives to decal are rated as following:
★★★★★  sticker
★★  label
★  license plate
★  cling
★  stencil
  bumper sticker
  decal

Your alternative for decal is not listed? Suggest!
Speaking about decal, one probably shouldn't forget about duck fish and deer.

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



Google Trends

Scale is based on the average worldwide traffic of decal in all years. Click on graph for more.
decal
sticker
label