Those offers existed back in 2010-2012, but today the longest 0% APR offer is an 18 month zero APR cards from Citi Bank.
But if you don’t need just a zero purchase APR but a balance transfer as well, have a look at the Chase Slate card with a 15 month intro zero APR for balance transfers and purchases with a 0 balance transfer fee. That combination makes the best balance transfer offer. In addition, even people with an average credit can obtain the card, which is a big advantage.