Also known as the Prisoner's Restriction, it is a multiple lipogram.

You are a prisoner in a solitary cell. You receive a small piece of paper and a pencil. In order to conserve space as much as you can, you decide to write only using letters that do not extend above or below the line. This means you may use the following letters only:

a, c, e, i, m, n, o, r, s, u, v, w, x, z

You can't use the letters:

b, d, f, g, h, j, k, l, p, q, t, y

Here is a fairly long list of words that can be created using the prisoner's constraint:

This list includes proper names and a variety of terms. Should be a sufficient vocabulary to get you started...