The best replacement for foregrip is bipod.

The best alternatives to foregrip are rated as following:
★★★★★  bipod
★★★★★  no foregrip
★★★★  quickdraw
★★★  afg
★★★  muzzle brake
★★★  bipod battlefield 3
★★  vertical grip
★  hand stop
★  heavy barrel
★  vertical foregrip
★  magwell grip
★  handstop
  angled foregrip
  angled

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

Other search terms related to foregrip and their ratings are:
★★★★★ bipod
heavy barrel
You have in mind a companion for foregrip and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of foregrip in all years. Click on graph for more.
foregrip
bipod
no foregrip