I'm of the opinion that anytime you try to use individual verses to back up a point, such as the point that nonbelievers will burn in hell forever literally, or the point that they might not, you have to take those verses into account against the backdrop of the context of the entire story that is the Bible, along with the context of the nature of God and the kind of Being we believe him to be. Because of that, I don't like to point to individual verses (even a group of them) as evidence that God might offer the opportunity of salvation after death, because I think it is dangerous to base an entire system of theology off of a select few verses. However, the fact that verses exist which point toward the ultimate redemption of all things is true, and I've provided a list of those I have come across (some of which are referenced in LW, some of which are not), as I have been asked to do by a few people (who I would hope, are also searching them out themselves). I am also familiar with the verses which seem to suggest that nonbelievers will spend forever in hell, however, I don't interpret them the same way as those who do believe that "once in hell, always in hell". In particular, the fact that "hell" in the N.T. always translates to "Gehenna" (a physical place in Israel) or to "Hades" (the Greek concept of death/the underworld) as well as the fact that "eternal" (aion) does not translate to "forever", give me pause in interpreting those verses in what might be considered a "traditional" sense. This is all to say that I don't consider any of the verses about hell found in the Bible to contradict any of the verses mentioned below, to ensure that I don't give the impression that I would use any verse to "refute" another.
If you end up looking these up, I definitely encourage you to read more than just the single verse in each case, if for no other reason than that it will be good for your soul and God said that the word that goes out from his mouth will never return to him empty but will accomplish what he desires (Isaiah 55:11).
John 1:29; 3:17 (*The verses following v. 17 speak of those who do not believe standing "condemned already". However it does not say anything about the nature of hell in this verse, or the impossibility of the condemned being redeemed.)
John 6:33; 6:51
Romans 5:18; 11:32; 13:10; 14:11; Isaiah 45:23
1 Corinthians 15:20
Colossians 1:19-20
1 Timothy 2:3-6
Interesting & Important:
"kolasin aionion" (translated "eternal punishment" in matthew 25:46)
Kolasin: "punishment, chastening, correction, to cut-off as in pruning a tree to bear more fruit"
*God punishes with a purpose, in this case, the purpose of pruning. How can someone who never gets to leave hell/punishment produce more fruit?
Aionion: "an indeterminate period of time. It could be as short as the time Jonah spent in the belly of a fish (three days or nights, and is used in that passage), the length of a man's life, or as long as a very long age."
Aionion does not equal "everlasting".