I understood a garniture was a set of items consisting of (a) matching pair/s and an odd item - most often seen as a set of three but does not have to be. So the set could be made up from two candlesticks and a clock, or two vases or urns and a bowl, or even, I suppose, two bowls and a clock, or suchlike combinations; or less commonly of five items, e.g. two candlesticks, two vases and a clock; or seven items, e.g. two candlesticks, two vases, two bowls and a clock, and so on. There's nothing that lays down that a garniture has to be a certain combination, so it could even be a larger vase and matching pairs of smaller ones - the only criteria are an odd number of items in total and matching pairs. Garniture literally means to garnish or embellish.
See here for more:US Antiques Roadshow page about garnituresExample of non-glass five-piece garniture set Ceramic three- and five-piece garniture sets