Treating today's OC-tober prompt of "symbolism" as an oc ask thing.
Colors:
-For my main 4 Blanksford OC I definitely use colors to represent them. Gabby's orange, Aeri's yellow, Madi's pink, and Taylor's red. There's not too much symbolism about these colors in particular other than visual design though. The concept of using colors for OCs gets a bit less helpful the more you have though. I tend to use a purply-pink or a blueish-grey for side characters.
Songs:
-I know some people are like crazy for OC playlists but that's just not how I usually listen to songs. I have occasionally heard a song and thought it'd be good for one of my OCs but it's super not common. The one that reminds me most of an OC for whatever reason is "Gravity Hero" by Rabbit Junk, making me think of Aeri.
Original Inspiration:
-Most of my oldest OC are named after like high school college crushes of mine, but I didn't take any like character inspiration apart from name. Aeri is very Chloe Price (LiS) -coded and as a result Gabby often takes some inspiration from either Max or Rachel depending on the scene. Artemis is very much Batman inspired and I'm constantly having to remind myself her story is better when it's uniquely hers and not just Batman fanfic.
Core Traits:
-When writing these characters I have a bunch of character traits that I keep in mind. For Aeri, she's always more scared than she lets on. Artemis wants to feel like she's in control, even if it means she's fooling herself. Taylor is overly trusting almost to a fault. Madi cares more for her friends than for herself. And Gabby doubts themself a lot when alone, but is easily empowered by their friends.