Are there any denominations in Christianity that believe that there is a way a person can go to heaven without accepting Jesus as the son of God?
St. Gregory of Nyssa believed that ultimately, all creatures will be reconciled to God. Unfortunately, that teaching didn't catch on.
The Eastern Orthodox generally hold that Orthodoxy is the true faith, and better conduces to union with God than any other religion or any other form of Christianity, but don't make any blanket statements about the fate of non-Christians or heterodox Christians. I remember my priest once asking me if I had heard of these fundamentalists who "really think that people who don't believe as they do will go to hell." He thought it was an odd and somewhat amusing belief.
It is the opinion of Father George Papademetriou that "the non-Christian may be saved in spite the religion he practices, but only through the mercy of God." St. Theophan the Recluse, asked whether it was possible for the heterodox to be saved, answered, "Why do you worry about them? They have a Saviour Who desires the salvation of every human being. He will take care of them. You and I should not be burdened with such a concern. Study yourself and your own sins." Bishop Kallistos (Ware) wrote, "It is heretical to say that all must be saved, for this is to deny free will; but it is legitimate to hope that all may be saved."
In the Catholic Church, at least three of the last four popes have affirmed that it's possible for non-Christians to be saved. (I don't know about John Paul I.) The Catholic Catechism says:
1260 "Since Christ died for all, and since all men are in fact called to one and the same destiny, which is divine, we must hold that the Holy Spirit offers to all the possibility of being made partakers, in a way known to God, of the Paschal mystery." Every man who is ignorant of the Gospel of Christ and of his Church, but seeks the truth and does the will of God in accordance with his understanding of it, can be saved. It may be supposed that such persons would have desired Baptism explicitly if they had known its necessity.
That seems to imply that people who are ignorant of Christianity have an advantage over people who have heard of Christianity but reject it, which reminds me of the story of the missionary and the Eskimo.
"If I didn't know about God," asked the Eskimo, "would I go to hell?"
"No," said the missionary, "not if you didn't know."
"Well then, why did you tell me?"
I don't know what Luther thought about it. Zwingli thought it was possible for non-Christians to be saved, and Calvin (predictably) did not. There is, however, a small group of Calvinist Baptists in the Appalachian region, the Primitive Baptist Universalists, popularly known as the "No-Hellers," who believe everyone will be saved. They believe that Christ died for the sins of all mankind, and so you will be saved whether you like it or not.
Or are there any denominations that believe that generally good people who aren't Christian go to a place such as limbo for example, while good Christians go to Heaven and bad people go to hell?
I don't know of any Christians who believe that anyone goes to heaven for being "good." In Christianity,
anybody who is saved is saved through the mercy of God.