Non-magical Equipment
tldr: I allow the spell to create non-magical equipment in my own games (as that seems to follow precedent and eliminates some problems)
True Polymorph seems powerful enough to generate equipment, as creating objects is one of its options. Also (as mentioned above): creating an unequipped creature would play havoc with its stats, which is not fun and would slow down the game. Such alteration of stats does not seem to be intended by the authors, as indicated by the phrases "The target's game statistics, including mental ability scores, are replaced by the statistics of the new form" and "The GM has the creature's statistics"
However, True Polymorph is apparently not powerful enough to create magical objects, as indicated by its description "You transform the creature into a different creature, the creature into a nonmagical object, or the object into a creature". Plus: generating magical equipment could create havoc with the game. My players seem very understanding of such a restriction... especially since they are seldom allowed to loot those same 'magical' items from fallen foes, similar to:
- Are Erinyes' Hellish Weapons poisonous in a PC's hands?
- If you kill a Solar Angel can you use its Slaying Longbow?
- What happens with the Drow's poisoned weapons when picked up by a PC?
- Do PCs get the attack and to hit bonus from enemy weapons they may pick up?
In play this means either the creature generates magical effects using mundane weapons, or some attack effects may not occur (depending on my own judgement as DM).