We are almost certain that Oats are not one of the 5 grains, but because of the extreme chumrah of Pesach, we refrain from eating it on Pesach. It may still be kept in the house without having to sell it.
Additionally, one should be very careful not to use Oat “Matzah” on pesach for the seder. It is readily sold in stores as a “gluten free option” for pesach. This is incorrect. It is not considered bread and therefore you are not Yotzeh the Mitzvah.
The correct bracha for Oat matzah and oat anything is Haadamah NOT mezonot.