Here are my personal guesses outside of the super obvious ones, with some brief reasoning.
Skar: I strongly suspect another member of Bridge 4 will become a Radiant, and while I do have another Bridgeman on the list, Skar is my suspect because he's one of the primary Bridgemen but he's also sort of low-key. Rock, Teft, Sigzil and Moash all have major plotlines already developing, whereas Skar is kind of just there as a solid dude. If we're to assume all the squadleaders of Bridge 4 will become thoroughly fleshed out, I suspect that Skar will be the one to undergo Radianthood. Personally, I'd guess Stoneward, given that his traits seem to line up with theirs.
Eshonai/Rlain (Shen): I'm in the camp assuming that we will see Parshendi becoming Radiants. I suspect that "uniting them" likely means many things, chief among them uniting all peoples in Roshar which would include the Parshendi. If you assume this as I do, Eshonai and Rlain seem like obvious choices. Otherwise, this would seem a stretch. Specifically, I'm expecting Eshonai to be a Bondsmith. There's a lot of reasons for this, but I've always read the chapter 58 Words of Radiance epigraph to suggest that a Bondsmith is responsible for something imposed upon the Parshendi, so it would seem appropriate if this is true that a Parshendi becomes that which once oppressed them. Bit of a stretch, though.
Gaz: Yeah, I know, I know. Huh? But I suspect Gaz will be the quintessential redemption story. A huge amount of Brandon's novels involve a character who is vile who betters themselves over a period of time, and I've had Gaz pegged for this since I showed up in Words of Radiance. I can't really peg him for any particular order, though.
Axies: Willshaper, specifically. I figure we have probably seen at least one eventual Radiant of every Order, and I've had Axies pegged as one since the description of Willshapers as being 'capricious, frustrating, unreliable,' and having a 'general love of adventure, novelty, or oddity.' This of course only works if you assume that non-humans will be able to become Radiants, which I evidently believe will be an important point moving forward in this generation of Radiants.
That's about it for my out-there predictions.