Not that I know of they fixed the old way to grow some of the familiars when the changed how metamorph marketplace items worked. People abused it and then people complained about it and then at some point the way it worked was changed. https://forums.daybreakgames.com/eq/index.php?threads/giant-familiars-pets.211620/
Oh, you mean can you make your familiar be bigger or larger? So sorry, I thought you meant grow one as in grow a plant or something.
The bug mentioned above was due to the modern dragon model used by the wizard AA familiar. That model is supposed to be huge, so to make a familiar out of them, they had to change their scale to something like 0.1 ... Well, when you used a metamorph item, it seemed to reset or overwrite the "scale" setting on the dragon model, so when you clicked off the illusion buff, you had a default (giant) sized dragon familiar! Even before they fixed the bug, the mimic chest wouldn't work like this because their default size is not very big. As far as I know, you can't grow or shrink familiars in any other way...