Many genera of Oncidium relatives have been moved around a lot. This leads to the old hybrid genus names, or nothogenera, becoming obsolete, and new nothogenera are used.
But species in the old genera frequently grouped together as far as cultural conditions. For example, the former genus Odontoglossum, now lumped into Oncidium, consisted almost entirely of cool to cold growing species. When you saw a nothogenus including Odontoglossum you could be fairly sure it wanted cooler conditions than some other intergeneric Oncidium hybrids.
You will still find a lot of plants sold under the old nothogenera. I look them up on the
RHS Nothogenera list, which I recommend people download and use for this purpose.
Some of the old, now obsolete nothogenera formed from former Odontoglossum species include Bakerara, Banfieldara, Beallara, Burrageara, Carpenterara, Colmanara, Dergarmorara, Howardara, Odontiopsis, Odontobrassia, Odontocidium, Odontonia, Vuylstekeara and Wilsonara.