Just using item NBT tags in GUIs and in Overlays on text labels. I tried to do this but it didn't worked. I couldn't find a ticket about this and actually I don't know if these are even possible but I guess it won't hurt to open a ticket for this.
MCreator issue tracker has been migrated to GitHub.
Existing tickets have been migrated to GitHub. Please open new tickets on the GitHub tracker instead. If you do not have a GitHub account, all feature requests and bug reports from forums are still considered and checked by the maintainers.