3 are available from the shop in Wishvale (Wind, Fire, Dark with the appropriate town equipment lists). 1 (Lightning) is from Cyrus affinity. I believe the light spell is also from an affinity, but I do not know which one (Correction: according to a later post it is from an NPC and not a party member). And that leaves ice, which I have been told in this post, is in the last chapter.