I am making "hero-builder" rpg with a lot of skills. All of my skills are Channel-based and I create 12 copies of eash skill for all slots on actionpanel, so players can freely choose skill layout for themselves. So I needed 12*skillcount free ids and I also like to take everything to extremes so I decided I need 3000+ ids in a row to be safe (who knows what crazy things I might think of in the future). Anyway I am generating skills in wurst so it's a question of changing 2-3 symbols and recompling.
For now I decided to use '!000-!ZZZ' range for my needs but thanks for help. Initially I planned to use 0-9,A-Z,a-z but found out that Widgetizer treats A-Z and a-z symbols as same when creating CampaignAbilityFunc.txt and CampaignAbilityStrings.txt so I wanted to try special symbols (I need Widgetizer since without it map can take ages to load or not load at all). I could just use 'E000-EZZZ' range or something similar but don't know I they are used for some hidden things like tilesets or lightning-ids.