Aunt/Uncle
Standard English doesn't have a gender neutral word for one's parent's sibling. People have created some words to fill this lexical gap, but they are still uncommon words. Alphabetical order.
Auncle. "Queer, combination of aunt and uncle."[24]
Bibi. "Queer, based on the B in NB [nonbinary], similar to Titi/Zizi."[25]
Cousin. "Neutral, as sometimes people say aunt/uncle for parents’ cousins, or much older cousins."[26]
Nini. "Queer, based on the N in NB, similar to Titi/Zizi."[27]
Ommer. Non-standard genderqueer term for "aunt/uncle".
Pibling. "Neutral, your parent’s sibling."[28]
Titi. "Neutral, from the Spanish for Aunt (Tia) and Uncle (Tio). (however, it is often a diminutive of aunt.)"[29]
Zizi. "Neutral, from the Italian for Aunt (Zia) and Uncle (Zio). (Note: zizi is also a French children’s ‘cute’ word for penis.)"[30]
Untie/Unty. "Queer, combination of uncle and auntie/aunty."[31]