Maísa

They had the Shards before they met Gavilar and the humans. In Oathbringer's prelude, Eshonai mentions that the listeners initially thought that their Shards, which they kept hidden from the humans. I suppose they kept these Shards for generations, since the Recreace or just after, since lots of Blades and Plates got lost since then.

I've got a question in mind, it would help with some theories.

That's why I think Dawnshards = Unmade. It's a bit unfounded theory, but "they were made and then unmade", which makes me think that they weren't originally from Odium, just got lost during the war against Odium.