Greenlight, the fintech company that pitches parents on kid-friendly bank accounts, has raised $260 million in a Series D funding round that nearly doubles its valuation to $2.3 billion. The funding comes just months after the Atlanta-based startup landed $215 million in funding at a $1.2 billion valuation. With the latest round, Greenlight has now raised over $550 million. Andreessen Horowitz (a16z) led its Series D, which also included participation from return backers TTV Capital, Canapi Ventures, Wells Fargo Strategic Capital, BOND, Fin VC, Goodwater Capital, as well as new…