The best replacement for teleconverter is extension tube.

The best alternatives to teleconverter are rated as following:
★★★★★  extension tube
★★★  telephoto
★★★  extender
★★  telephoto lens
★★  crop
★★  mirror lens
★  cropping
★  crop sensor
★  digital zoom
★  close up lens
★  diopter
★  barlow
★  extension
  macro lens
  tamron teleconverter
  kenko
  2x
  extension tubes
  canon teleconverter

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

Other search terms related to teleconverter and their ratings are:
★★★★★ zoom lens
★★★★★ macro lens
★★★★ nikon 70-300
★★★★ 50mm lens
★★★★ extension tube
★★★★ nikon 80-400mm
★★★ tamron 70-300
★★★ sigma 150-500
★★★ 70-200
★★ canon 70-300
★★ tamron 18-270
★★ 85mm
★★ macro
★★ 18 200
★★ canon 100 400
★★ nikon 18 200mm
★ nikon 28 300
★ macro lenses
★ 24-70
★ 70 200mm vr
★ sigma 150 macro
★ 28 300mm lens
★ nikon 55-300
★ nikon 70 200
★ nikon 18 200
★ nikon 70 200 vr
70 200
nikon 70-300 vr
nikon 70 \/ 200 mm vrii
nikon 80 400
teleconverter
nikon 70 200 mm vrii
nikon 70 300 vr
You have in mind a companion for teleconverter and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of teleconverter in all years. Click on graph for more.
teleconverter
extension tube
telephoto