The meteg (ga'ya) is one of the most common accents in the Hebrew Bible, and it serves two functions: phonetical & musical. It indicates a secondary accent. We said 'accent', but it is not really an accent.
The meteg is marked by a short vertical stroke under the word, and generally before the stress syllable. It resembles the siluk, but has different functions (both are uni05BD).
Grammatically(1) there are ten different kinds of metegs.
(1). If the phonetical & musical functions are under one umbrella.