I think major emotional responses are rooted in the structure of our brain- determined by our biological makeup- and perhaps we've discovered all the "major types" so to speak, there.

However, I could see this changing with 1) augmentation (just as magnets implanted in the fingertips are already allowing humans to harness magnetoception as a seventh sense) or 2) awareness, categorization, or study into emotions gives names to increasingly subtle facets of emotion.

However, for the first, augmenting the brain in a way that could provide it with new emotions could be a highly complex undertaking. After all the permutations of stimulation of existing brain structures are explored, the only extension would be hugely more technologically difficult (providing new structures for the brain to operate with).

And for the second, there are diminishing returns of a kind when discovery comes from increasingly minute categorization. At some point, without changing the resolution at which people are able to identify emotions in themselves, such investigations become "pointless nomenclature" or "splitting hairs" to the average person. And while it may be useful for, I don't know, further theoretical modeling of emotions, if it doesn't lead to something that has practical use for this average person, it may fall out of favor.