The best replacement for mega bloks is lego.

The best alternatives to mega bloks are rated as following:
★★★★★  lego
★★★★  duplo
★★★  playmobil
★★  lego duplo
★★  legos
★  lightning spirit
★  kreo
  lego halo
  lego youtube

Your alternative for mega bloks is not listed? Suggest!
Speaking about mega bloks, one probably shouldn't forget about duplo.

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



Google Trends

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mega bloks
lego
duplo