Caricatures are drawings of people, but proportions and
 characteristics are usually either overexaggerated or
 oversimplified beyond recognition. These drawings can be
 either insulting or complimentary towards a person,
 but are usually meant for humor.

 Silhouette drawing is pretty simple style that is
 basically just drawing a filled-in outline of a subject
 in front of light-colored backgrounds.
 Back then, it was used a an easy alternative to painting
 a portrait of someone, but it's still used to this day
 as a way to draw a simple portrait.

 Sketching is used for a few different things. These include
 courtroom sketches, croquis (fashion), studies, or even
 scribbles.
 Sketching can be used in either a professional field or
 by amateurs who love to draw. Sketching is one of the most
 common forms of drawing, since anyone can do it.

 Technical drawing involves illustrating plans for a building,
 machinery, or other things. The main types of technical
 drawings include architectural, electrical, engineering,
 plumbing, structural, mechanical systems, or scientific
 illustrations. These plans that these drawings illustrate
 are then implemented in real-life.