This is the hard limit. Server plugins can simulate new items (e.g., a stick renamed to “Lightning Wand” that executes a command), but they cannot render a new 3D model on the client. The Eaglercraft client has a fixed set of blocks and items. If the client doesn’t have a model and icon for “Titanium Ore,” you’ll see a purple/black checkerboard or nothing at all.
If you are a developer, you can modify the game by setting up a workspace with the Eaglercraft source code. can i add mods to eaglercraft