garnishes that involve fancy cuts

> very easy

Citrus:

• paring knife
• zester   (the type that's often attached to a channel knife)
  • tribal ^†
• Y-peeler
• channel knife

> easy

Citrus:

• twist   [2]
• double twist ^†
• cross-bow ^†
• bird ^†
• star
• four-leaf clover
• triangle divider
• and the related sun

† High bang-for-the-buck, in terms of having a lot of visual interest while not requiring a ton of work.

> harder

• bird, a variant of cross-bow

citrus fruits I prefer

[1] [2] [3] (I prefer them because they have the best contrast)

• limes:
  • ginger lime
  • key lime
  • ~Persian lime
• oranges:
  • blood orange — Striking color.
• lemon — Ok contrast between the skin's surface and the inner whiter skin.
• mandarin orange — Ok contrast between the skin's surface and the inner whiter skin.
• pomelo — But only if the outer skin is green. (note that the color can change depending on ripeness)