Maltose (Malt Sugar): Maltose is found in malt which is germinated barley seed. Maltose is a minor constituent of the American diet.
Stachyose (Bean Sugar): Stachyose is the sugar in beans that many humans cannot absorb that causes intestinal gas.
"Oligosaccharides" are typically defined as chains of between three and ten sugars and tend to be a sort of hybrid molecule with some of the properties of sugar and some of starch. Oligosaccharides are not a common household food and may be rather unfamiliar to people, but some examples of oligosaccharides include stachyose (the stuff that makes beans 'gassy') and some of the carbohydrate in malt sugar, especially "maltotriose"- a trisaccharide. Interestingly, a tetra(four)-saccharide called "acarbose" is also an approved drug for the treatment of type-2 diabetes because it is not only indigestible but also blocks the effects of an oligosaccharide-digesting enzyme called alpha-glucosidase therebye rendering much of the starch in a meal indigestible to humans. This effect of acarbose is useful since it dramatically lowers the glycemic load of a meal. The only problem with this effect of acarbose is that undigested starch will pass to the colon wherein bacteria can digest it resulting in gas. Acarbose is a class of compounds that are also known as "starch blockers".