The best replacement for shading is lining.

The best alternatives to shading are rated as following:
★★★★★  lining
★★★★  tinting
★★  outline
★  hatching
★  illumination
★  deferred lighting
★  soft shading
★  outline pain
★  cel shading
  pixel shading

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

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



Google Trends

Scale is based on the average worldwide traffic of shading in all years. Click on graph for more.
shading
lining
tinting