The best replacement for red onions is white onions.

The best alternatives to red onions are rated as following:
★★★★★  white onions
★★  yellow onions
★★  yellow
★★  shallots
★  purple onions
★  sweet onions
  green onions
  spanish onions

Your alternative for red onions is not listed? Suggest!
Speaking about red onions, one probably shouldn't forget about poppadoms.

Other search terms related to red onions and their ratings are:
★★★★★ poppadoms
★★★ popadoms
You have in mind a companion for red onions and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of red onions in all years. Click on graph for more.
red onions
white onions
yellow onions