The best replacement for 2d is 3d animation.

The best alternatives to 2d are rated as following:
★★★★★  3d animation
★★★★★  3d
★★★  3d movies
★★★  3d tv
★★★  3d shapes
★★  3d ultrasound
★★  not 2d
★  3d games
★  3d cad
★  3d barcode
★  3d seismic
★  2d
★  2nd
★  3d mammography
★  3d graphics
★  3d cell culture
★  3d zelda
★  1d barcode
  3d culture
  3d hobbit
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  3d projector
  1d
  3d gravity
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  3d avengers
  3d fighting games
  3d blu ray player
  4d ultrasound
  3d tangled
  3d graphics cards
  3d thor
  2.5d
  imax 3d
  1m tip
  3d barcodes
  3d ultrasounds
  3d cinema
  3d which is better
  3d man of steel
  3d vision

Your alternative for 2d is not listed? Suggest!
Speaking about 2d, one probably shouldn't forget about unity 3d.

Other search terms related to 2d and their ratings are:
★★★★★ unity 3d
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