Luffy’s a given, even if we don’t find out about his mom we’ll almost certainly learn why his dad left him to be a revolutionary
Zoro might but frankly if we didn’t hear about it in Wano I don’t know when we would
Nami also might because we don’t know about her parents before Bellamere but at this point it’d be hard to fit that into the end of the series
Franky is possible too because his parents were pirates so we could potentially see them.
Usopp is going to meet his dad so we could get something there
We don’t know about Robin’s dad I guess but that seems unlikely to be addressed
Chopper is literally just a reindeer so it seems like we won’t get anything there