As of 4.4.0, you can specify any hex color you want when using the dye commands. This changes the number of available colors from around 140 to 16,7 million.
This blog post shows how to get a hex number from colors and how to use the command in-game to apply it.
How to get a hex number
Go to, for example, https://rgbacolorpicker.com/hex-color-picker
Select a color you want
Copy the 6 numbers and digits AFTER the #.
This is the hex number that you will use in-game.
How to use the in-game commands
The available commands are:
/dyea <hex> <- Sets the "Clothing Dye", aka the main color.
/dyeb <hex> <- Sets the "Accessory Dye", aka the secondary color.
/dyeboth <hex> <- Sets both to the same color.
Example to set the main color to the purple above:
If you need more assistance, you can open a ticket or ask in #ascended on Discord.
Pssst... They also show up with the correct dye on player cards now!