So while making charts I kept wanting a reference for all the character backgrounds, so here's a guide to be that reference!

Each character will have their CharacterID, (approximate) Background Colors, and Particle effects listed.
The CharacterID can be used in both the vfx.json and the info.json. The info.json's "Counterpart" changes both the background and portrait while the vfx.json's "CharacterID" only changes the background and is prioritised over info.json's background.
Some also have additional info in a Note, often about the method of adding the portrait (which differs for older and newer DLC characters)

This guide won't go in-depth on how to change the Backgrounds and Portraits. For that please check out this guide:
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3487821958

CharacterID: NecrodancerCloak
BG Colors: Purple
Particle effects: Skulls, Bone

CharacterID: NecrodancerBurger
BG Colors: Salmon Pink
Particle effects: Drink, Milkshake, Hamburger

CharacterID: Dove
BG Colors: Light Yellow
Particle effects: Feathers

CharacterID: Heph
BG Colors: Dark Green
Particle effects: Anvil, Hammer

CharacterID: Merlin
BG Colors: Dark Blue
Particle effects: Sparkle, Diamond, Dot

CharacterID: Nocturna
BG Colors: Burgundy, Red
Particle effects: Bats

CharacterID: Suzu
BG Colors: Desaturated Purple
Particle effects: Dust Clouds, Gusts

CharacterID: Harmonie
BG Colors: Bright Pink
Particle effects: Hearts

CharacterID: Queen
BG Colors: Deep Blue
Particle effects: Petals, Flower

CharacterID: Matron
BG Colors: Dark Gray/Grey/Graey
Particle effects: Broken Notes, Treble Clef

CharacterID: Reaper
BG Colors: Desaturated Purple and Green
Particle effects: Wisps

CharacterID: Beastmaster
BG Colors: Spring Green
Particle effects: Pawprint, Triangle, 💤(?)

CharacterID: Shopkeeper
BG Colors: Bright Purple
Particle effects: Coins

CharacterID: Coda
BG Colors: Bright Purple
Particle effects: Knifes, Hit Particles (💥)

CharacterID: NecrodancerCrypt
BG Colors: Purple
Particle effects: Skulls, Bones
Note: Necrodancer Crypt's background is identical to Necrodancer Cloak
Note: Portrait can be added via CustomPortRift

CharacterID: Apricot
BG Colors: Bright Red
Particle effects: Buzzsaws, Small Diamonds
Note: Portrait can be added via info.json

CharacterID: Banana
BG Colors: Bright Pink
Particle effects: Strawberry, Sparkle
Note: Portrait can be added via info.json

CharacterID: Banana02
BG Colors: Bright Pink
Particle effects: Strawberry, Sparkle
Note: Portrait can be added via info.json

CharacterID: Cherry
BG Colors: Hot Pink
Particle effects: Cheese Slice, Tomato Slice, Mushroom
Note: Portrait can be added via info.json

CharacterID: Kiwi
BG Colors: Cyan, Blue
Particle effects: Notes, Leek
Note: Portrait can be added via CustomPortRift

CharacterID: Guava01
BG Colors: Bright Blue, Aqua
Particle effects: Triangles, Notes
Note: Portrait can be added via CustomPortRift

CharacterID: Guava02
BG Colors: Bright Blue, Blue, Aqua
Particle effects: Triangles, Notes
Note: Portrait can be added via CustomPortRift

CharacterID: Guava03
BG Colors: Salmon Pink
Particle effects: Triangles, Notes
Note: Portrait can be added via CustomPortRift

CharacterID: Guava04
BG Colors: Salmon Pink, Yellow, Gold
Particle effects: Triangles, Notes
Note: Portrait can be added via CustomPortRift

CharacterID: Guava05
BG Colors: Bright Blue, Aqua
Particle effects: Triangles, Notes
Note: Portrait can be added via CustomPortRift

CharacterID: Eggplant
BG Colors: Hot Pink, Green
Particle effects: Sparkle, Everhood Skull, Everhood Slash
Note: Portrait can be added via CustomPortRift

CharacterID: [Anything that's not already a CharacterID]
BG Colors: Blue, with stars!
Particle effects: None
Note: This doesn't come with the any portrait by default if edited via info.json

CharacterID: Mango01 (there are multiple Mango's but I haven't checked yet, my guess is it goes up to 05)
BG Colors: TBA, Various
Particle effects: Monstercat, Sparkle
IMAGES TBA

It's also possible to make your own custom backgrounds using the vfx.json. That's why in this section I'd like to showcase some of the charts that use custom backgrounds people have made.

If you want to include your's in here feel free to let me know in the comments or any other arcane way of contacting me.

If you want more information on how to make custom backgrounds (or portraits!), check out this guide: https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3487821958
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3422450367 https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3536014343 https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3527703690 https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3545574757 https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3551485020 https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3488835630

If you have any feedback or I made a mistake, let me know!

If this guide was helpful feel free to Like this guide :>

Special thanks to:
96 LB - For their Custom Portrait Guide for being greatly informative and without it this guide wouldn't exist
Bingus - For the full list of DLC codenames that they posted in the discord