This whole list is in a random order.
-Ones from the list I picked up-
Fall: I was able to remember the name, the fact he had red hair, and the fact he had crystal abilities
Xene: She's a weird case, I partially remembered her name (I knew it started with Xene, but forgot the rest), and remembered that she had glasses
The Warrior: I only really remembered that they had a cloak, but obviously they reappeared in a different dream and there I remembered that they looked really similar to Cynthia
Black and Whitney both basically kept their original designs, while Maurice kept his name
Dark: I remembered she looked almost identical to the Knight from Hollow Knight
Chrono: I remembered that he was a Lucario, that he had armor, and that he had a Venusaur as an ally (Which I later changed to a Braixen for reasons involving my ongoing quest to loophole out of copyright issues with using Pokemon in game projects)
Viora: I was able to remember that she was an endgame summoner (vanilla), mostly because of how she kinda totally destroyed the Lunatic Cultist with a maxed out Stardust Dragon
Nathan: Said Lunatic Cultist that got destroyed by Viora and her maxed out Stardust Dragon
Ateas: was actually mentioned as being the embodiment of hate
Alan: Apparently he used to be a very powerful mage at some point, but lost his powers
Harmony: She's an amnesiac, who also happens to be the embodiment of harmony (as an emotion)
Chara (VoidTale): She had some... plans for the surface, to put it lightly
Exel and Yvena: I remembered their roles, and how they were only mentioned as "the assistants" and never by name
-Everyone that came after that I can think of-
This part of the list will also include characters I already had when I made the above list, but that I just forgot about or didn't mention.
Lazyl: Similarly to Xene, I was able to remember his name, and a few appearance details, specifically him having long green hair and being really tall.
Frost: Edge case with being new (she wasn't really new when she appeared in this dream, like at all), but she was very different when she appeared in the same dream as Lazyl. More confident than before, kind of a goth, and used a warhammer in battles. I think she got annoyed at me ignoring her existence and had a character arc while waiting.
In that same dream, there was also a boy who was heavily implied to have some relation to Lazyl, at a few points being implied to be the same person as him. That's all I really remember about him.
Noelle is... a REALLY unique case. I mostly remembered what she sounded like, somehow.
Rine: I remembered that she had a trident, and actually lived in an underwater town of sorts.
Pendant: Remembered that she was super quiet and just generally a weirdo.
Samantha: She was a background character who I think was mentioned by name in one dream, I just made her important later.
Quill: Remembered his abilities (Earth, Wind and Water magic, was first shown obtaining Wind magic).
Charm: Was able to remember his name, and his mask (and that the mask limited his powers)
Vey: Remembered name and that he was Charm's enemy (and was stated to have been his enemy for a long time)
Iltum: Was originally shown as a Sneasel, then later in the same dream as a Weavile, and was heavily implied to have pretty strong mind-control
Six: I remembered his username. His real name was never mentioned, but the dream he's from sort of took place in a Minecraft server, and his username was shown as SuccessfulSix. I later shortened that to make his nickname.
Leah: Remembered her name (I think...), but not much else
Prayer: Remembered his appearance (he looks kinda similar to a Ledian)
I'll mention Dan and Purple here real quick but they're a long story. By a bajillion technicalities, they're not even truly my characters, as they're based on the other players from my first multiplayer Terraria run. (Purple's name is based on the name of the character the player he's based on, which was PurpleSonic)
My brain is kind of failing right now, I'll keep this document for future updating (and for whenever there's new characters for me to add in).