The large moth family Gelechiidae contains the following genera:

Ochmastis Octonodula Oecocecis Oegoconoides Oestomorpha Oncerozancla Onebala Opacochroa Ophiolechia Organitis Origo Ornativalva Orsotricha Orthoptila Oxylechia Oxypteryx

References

Natural History Museum Lepidoptera genus database