Here's a bunch of ships to consider. Jason/Calypso, Will Solace/Thalia, Will Solace/Leo, Jason/Ethan, Percy/Athena, Ethan/Alabaster, Magnus/Jason, Percy/Khione, Triton/Thanatos. Thoughts?
Jason/Calypso (Jalypso, Calypson) : Ok anon you will listen to me very carefully... I love Jalypso. This ship is gold tier, this ship is awesome this ship is... gods it's just wonderful, ok ?!! I adore this ship, Calypso and Jason could have one of the cutest relationship in the entire Riordanverse (yes I love them that much). Just all of you should try to think about Jalypso, it's wonderful (two cuties with a big heart who would hurt anyone who threatens their love ones ? A-do-ra-ble.).
Will/Thalia (Willia, Thil) : Oh yes ! I've thought about it and it's really cute too. Thalia is the kind of demigod who's always "too" invested in capture the flag, so she would end up in the infirmary a LOT. I'm totally on it for a friendship between the two, and as a couple ? Yes, a thousand time yes !
Will/Leo (Willeo) : Again, a really cute ship. The two are nice, the two are fun and the two are protector. Will has a lot of love to give and Leo could need that. They certainly would have a lot of fun together. (And Naomi and Leo would love each other, she could be like a mother to him too. + country music at every family dinner, Leo would love it).
Jason/Ethan (Ethason, Jasan, Ethon) : Ethan is in a big need of affection and Jason gives affection (he's not really good at understand it but he gives a lot of it). So why not ? Actually it sound REALLY good and I'm really interested by it.
Percy/Athena (Perthena) : Like I said a few days ago, it's not really my thing. A good fanfic material, but that's it.
Ethan/Alabaster (Alan, Ethaster, Ethabaster) : Yes, yes, yes, yes yes yes yes yes yes... YES ! I shipped it at the moment I met Alabaster in Son of Magic.
Magnus/Jason (Mason, Jagnus) : Already told what I think about this one, two words : absolute cuteness.
Percy/Khione (Percyone, Khiocy) : ... Wahou... And I thought I had crack ship. I'm impressed anon, sincerely impressed. But... I really don't know what to say, when I first saw your ask, I almost laughed, like... I thought it was ridiculous. But have to admit that more I think about it... more I like it. It's crack, probably one the most crack RR ship I've ever seen (the most one being the next one), but it could be cool (haha... sorry). Water and Ice loving each other, Percy could make melt Khione's heart, help her to be less cold and warm her (no seriously I love this jokes). I think Percy and Khione could be really interesting, and I'll look forward to it.
Triton/Thanatos (Tritos, Thanaton) : ........ whaaaat ???? Ok, ok, ok, but seriously... I kind ok like it. Triton is arrogant and Thanatos seems to be the "too strict forward to be appreciated" type of guys, it could work. I don't ship lots gods but this pairing is unusual, has a certain logic and lovely, all I want from a ship. So again, why not ?
Thank you for all this ships anon, what I can resume from all of that is : crack ships but good ships, cuties, lots of cuties, and Jalypso... just... Jalypso