The best replacement for magnifier is acog.

The best alternatives to magnifier are rated as following:
★★★★★  acog
★★★  variable scope
★★★  scope
★★★  eotech
★★  primary arms
★★  eotech g33
★  1-4 scope
★  eotech magnifier
★  aimpoint magnifier
★  5x
★  vortex
  5x magnifier
  trijicon acog
  loupe
  aimpoint

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

Other search terms related to magnifier and their ratings are:
★★★★★ light
★★ red dot
★★ eotech
★★ lamp
★★ eotech 512
★★ flip to side mount
★★ trs 25
★ aimpoint pro
★ iron sights
★ acog
You have in mind a companion for magnifier and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of magnifier in all years. Click on graph for more.
magnifier
acog
variable scope