Suggestion: Only load the minimal set to enable the listings in the UI, not the entire record. Stop doing this, it's bad. The ability to pull content into a game from another game via the Transmogrifier should be a convenience feature, not a required performance enhancer for your game. Loading content via AJAX / Fetch API is nothing new, there's no valid reason to load every field for every character in a game. There's no valid reason for "too many spellcasters" to cause a performance hit, when those character sheets aren't even open on anyone's screen. Doing this would also remove one of the many steps that end users have to troubleshoot/rule out on Roll20's behalf when we experience lag issues.