The best replacement for horizons is saxon.

The best alternatives to horizons are rated as following:
★★★★★  saxon
★★★★  singapore math
★★★★  lifepac
★★★★  abeka
★★★★  medicare
★★★★  math u see
★★★  abeka math
★★★  teaching textbooks
★★  monster ftb
★★  kindercare
★★  saxon math
★★  math mammoth
★  direwolf20
★  singapore
★  humana
★  lifepac math
★  mission space
★  ishares
  sonlight
  scan
  cle math

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

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



Google Trends

Scale is based on the average worldwide traffic of horizons in all years. Click on graph for more.
horizons
saxon
singapore math