The best replacement for breaststroke is freestyle.

The best alternatives to breaststroke are rated as following:
★★★★★  freestyle
★★★  butterfly
★★  front crawl
★★  breastroke
★★  sidestroke
★  crawl
★  sidestroke faster
★  side stroke
★  freestyle triathlon
★  breaststroke
★  backstroke
  butterfly swimming
  front crawl triathlon

Your alternative for breaststroke is not listed? Suggest!
Speaking about breaststroke, one probably shouldn't forget about dolphin kick.

Other search terms related to breaststroke and their ratings are:
★★★★★ dolphin kick
★★★★ flutter kick
★★ head out of water
You have in mind a companion for breaststroke and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of breaststroke in all years. Click on graph for more.
breaststroke
freestyle
butterfly