I like to introduce distortions and color effects into my videos when I edit them. How can I recreate color banding in After Effects or Premiere Pro?
Adding colour banding is also known as posterising (or posterizing if that's how you roll). There's a built-in (to AE, though I'd be surprised if it's not also in PP) posterize effect (Effects>Stylize>Posterize). It only has one control, Level, if you set it low you'll get something that looks like an 8-bit game, or a screen-printed poster (hence the name):
Or if you set it higher you get banding:
If you want a bit more control the Cartoon effect (Effects>Stylize>Cartoon) also give you pronounced banding. Set the render style to Fill (default is Fill & Edges), and then twiddle the knobs.