In John 15, what did Jesus call himself?

Answer: The true vine

Jesus said, 'I am the true vine, and My Father is the keeper of the vineyard... you are the branches.'

““I am the true vine, and My Father is the keeper of the vineyard. I am the vine and you are the branches. The one who remains in Me, and I in him, will bear much fruit. For apart from Me you can do nothing.”— John 15:1, 15:5 (BSB)