The best replacement for pebbles is mulch.

The best alternatives to pebbles are rated as following:
★★★★★  mulch
★★★★  rocks
★★★  cocoa krispies
★★  gravel
★★  bark
★★  stones
★  cocoa puffs
★  cocoa pebbles
★  coco
★  tlc
★  coco puffs
★  lucky charms
★  fdr
  cobbles
  fruity pebbles
  fruit loops
  pea gravel
  trix

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

Other search terms related to pebbles and their ratings are:
★★★★★ tlc
★★ epoxy
resin
You have in mind a companion for pebbles and it is not yet here? Propose!



Google Trends

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pebbles
mulch
rocks