The best replacement for carbon fiber is fiberglass.

The best alternatives to carbon fiber are rated as following:
★★★★★  fiberglass
★★★★★  aluminum
★★★  titanium
★★★  kevlar
★  aluminum bike
★  graphite
★  aluminum weight
★  steel strength
★  carbon kevlar
★  titanium road bike
★  aluminum tripod
★  g10
  aluminum bikes
  aluminum bike frames
  steel weight
  wood bow
  carbon fibre
  fiberglass hood
  aluminium
  clear lid
  aluminum strength
  aluminum road bike
  fiberglass hoods
  aluminum arrows
  fiberglass strength
  steel road bike
  aluminum frame
  kevlar clutch
  steel bike
  graphite fiber
  aluminum tripods
  urethane
  fiberglass weight
  titanium bikes
  titanium bike frames

Your alternative for carbon fiber is not listed? Suggest!
Speaking about carbon fiber, one probably shouldn't forget about fiberglass resin.

Other search terms related to carbon fiber and their ratings are:
★★★★★ fiberglass resin
★★★★★ epoxy resin
★★★★ polyester resin
★★★ polyester resins
★★ peek
You have in mind a companion for carbon fiber and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of carbon fiber in all years. Click on graph for more.
carbon fiber
fiberglass
aluminum