Lancelot
Adventurer
Every magic item I've used so far in my two 5e campaigns has been above-and-beyond a normal +1 magic item.
For example: A +1 magic longsword bearing an ancient dwarven name. The possessor of the sword starts growing a thick beard (regardless of race or gender). Once every 3 or 4 combats, the wielder (unconsciously) utters a dwarven oath in battle. After performing a side-quest to honor the dwarven gods, the wielder may actually attune themselves to the blade and gain either darkvision or resistance to poison. Similarly, a +1 magic battleaxe made of transparent crystalline steel, and weighing only one pound. The axe becomes invisible the first time it is swung in combat, granting the wielder Advantage on their first attack roll unless the target has Blindsight or Truesight. After hitting a creature, the axe must be scrupulously cleaned and polished (taking a Short Rest) before it regains its ability to become invisible on the first strike again.
So, what I'm looking for in the DMG is more of the same. I want items with quirky powers. If we're talking "old favorites", I'm thinking sunblade, sword of the planes, rod of lordly might, cube of force, decanter of endless water. All of those items had multiple functions, and are going to be the most likely to have the level of "quirk" that I'm looking for.
For example: A +1 magic longsword bearing an ancient dwarven name. The possessor of the sword starts growing a thick beard (regardless of race or gender). Once every 3 or 4 combats, the wielder (unconsciously) utters a dwarven oath in battle. After performing a side-quest to honor the dwarven gods, the wielder may actually attune themselves to the blade and gain either darkvision or resistance to poison. Similarly, a +1 magic battleaxe made of transparent crystalline steel, and weighing only one pound. The axe becomes invisible the first time it is swung in combat, granting the wielder Advantage on their first attack roll unless the target has Blindsight or Truesight. After hitting a creature, the axe must be scrupulously cleaned and polished (taking a Short Rest) before it regains its ability to become invisible on the first strike again.
So, what I'm looking for in the DMG is more of the same. I want items with quirky powers. If we're talking "old favorites", I'm thinking sunblade, sword of the planes, rod of lordly might, cube of force, decanter of endless water. All of those items had multiple functions, and are going to be the most likely to have the level of "quirk" that I'm looking for.