To limit the massive territory of how Protestants differ from Orthodox, I'm going to filter it down a couple times.
First, I'm not going to include points that the Orthodoxy and Catholicism agree on that Protestants (typically) disagree with: that the Eucharist is the body, soul, and divinity of Christ; that Mary is the Mother of God; Apostolic Succession; iconography; sacraments; communion of the saints; rejection of the Protestant solas; contemplative prayer & mystical theology; etc. The reason for this is that you can learn about all these points just from reviewing the Catholic-Protestant debate.
Second, I'm not going to include points that Protestantism and Catholicism agree on that Orthodox disagree with or don't share: original sin, the entire Augustinian framework, the strong emphasis on scholastic theology, a general emphasis on the sacrifice of Jesus' crucifixion rather than the Incarnation as the locus of salvation, some degree of reticience around hesychasm & Palamian theology, filioque, etc.
I could be wrong, but once you cross out all that stuff, I think all you're left with is the Pope, in Catholic understanding the principle of unity of the Church. Of course, Orthodox and Protestants "agree" on this in completely different ways, since Protestants reject the Orthodox understanding of apostolic succession that the Catholic papal ecclesiology requires, so I would be hard pressed to call this a point of true agreement.