Are backyard lizards poisonous

No - they're a non-venomous species. I couldn't find that much info - but I DID find something on Wikipedia - See related link the real alligator lizard are not the most venomous it is not the mostcommon lizard in living with people

No. Only two lizard species [Heloderma suspectum (Gila monsters-2 subspecies) and Heloderma horridum (Mexican Beaded Lizards-4 subspecies)] are venomous.