Some chord shapes

As you can see below, many chords can be built up by adding notes one by one as indicated by the Direction column to the shape in the Shape column. For some of the larger chords, one may miss out one or more previous notes; Eg in a Major 9th the 7th (second to highest note) may be missed out.
On a keysurface a major or minor triad can be played with one finger pressing between the three notes, and a 7th or 9th can be played with only two fingers.

Of course, not all chord shapes are clumped together like this. There are many others.

For more, see the Chord Calculator.