First three letters of Abzan are a,b, then z. Then a again. Like a life cycle. You're born, you grow, you die, then you get resurrected by one of Abzan's many graveyard tricks.
Bant is like "banter", like friends do. It's the friendly colours of white, blue, and green. It helps that my group hug and pillow fort decks are both bant to help me glue that association together.
Sultai starts with an "S", hissing like a snake. Vraska has snake hair and she's green/black, but sultai also follows the S with a U to remind you blue is in there.