A creamer is a small pitcher or jug designed for holding cream or milk to be served with tea or coffee in the Western tradition.
[1] The competition between two collectors for an especially valuable silver cow creamer is a plot-line in P. G. Wodehouse's novel The Code of the Woosters.
In this context they are referred to as espresso brew pitchers, and also billed as "small creamers".
Espresso brew pitchers are particularly used for layered latte macchiatos, which require careful pouring.
In other drinks, an espresso cup or shot glass is a common alternative, which must be dumped rather than poured.