The best replacement for sleeping bag is quilt.

The best alternatives to sleeping bag are rated as following:
★★★★★  quilt
★★★  wool blanket
★★★  blanket
★★  air mattress
★★  bed rust
★  duvet
★  synthetic
★  swaddle
★  sleeping pad
★  slumber bag
★  blankets
★  bivy sack
★  nap mat
  sleeping mat
  wool blankets
  rectangular
  bivy
  tent
  sack
  down

Your alternative for sleeping bag is not listed? Suggest!
Speaking about sleeping bag, one probably shouldn't forget about air mattress.

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



Google Trends

Scale is based on the average worldwide traffic of sleeping bag in all years. Click on graph for more.
sleeping bag
quilt
wool blanket