to get another random color gradient scheme enter
!randomColors

if you prefer the game standard setting use
!standardColors

if you fancy choosing your own colors do as follows
use https://fliegenfuerst.github.io/ff7/gradient-editor/ to get edit your chat background settings :
-click the respective corners of the preview to select them
-use the sliders to adjust colors or click the preview color box to open a colorpicker
-to reset the editor colors to standard ff7 settings click default
-click on 'copy chatmessage' to copy the settings into the clipboard so you can paste them into twitch chat to change your chat background settings

bonus:
use !fortune to get your digimon world 1 airdramon fortune telling for the day