The best replacement for watercolor is acrylic.

The best alternatives to watercolor are rated as following:
★★★★★  acrylic
★★★★  gouache
★★★  oil painting
★★★  seaside
★★  watercolor
★  watercolor pencils
★  ink first
★  watersound
★  watercolour
★  rosemary beach
★  oil paint
★  lithograph
★  acrylic paint
  acrylic painting
  pastel
  gouache paint
  acrylic paints
  tempera
  gauche
  copic markers
  copic
  rosemary

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

Other search terms related to watercolor and their ratings are:
★★★★★ salt
★★★ ink
★★★ pen and ink
★★ acrylic
★ colored pencil
★ crayon
★ sharpie
★ distress ink
boundaries exploring ways to have fun with watercolor
white crayon
graphite
You have in mind a companion for watercolor and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of watercolor in all years. Click on graph for more.
watercolor
acrylic
gouache