Tales and Chronicles
Jewel of the North, formerly know as vincegetorix
I've done it and it works great, but I spread the feat's bullet points a little, so no item that grant the whole GWM feat. This way the effects can affect more items.
Axe of Cleaving: When you drop a creature to 0 HP, can make a weapon attack as a bonus action.
Gauntlet of Weapon expertise: Gain proficiency with 3 weapons types.
Gauntlet of Weapon Grand Mastery: You can take -5 on attack rolls to gain +10 damage on a hit.
Falconer goggles: Ignore 1/2 cover and long range penalty.
Crossbow of speed: This weapon loses the loading trait.
X (medium armor) of Comfort: Max dex bonus to AC is 3 instead of 2. Ignore stealth penalty.
Ring of X (elemental type) adept: Ignore resistance to X element and reroll 1-2 on damage rolls.
X (medium of heavy armor) of the Squire: This armor grants proficiency with X armors and shields.
You can even make equipment sets ala Diablo:
Delver's armor: Resistance to traps damage and advantage to saves against trap.
Delver's helm: Advantage to spot traps and secret doors.
Delver's boots: Doesnt not have a penalty when walking at fast pace.
When the Delver's armament is assembled on your person, you can cast Detect Trap, Knock and Arcane Lock once per day each.
etc
Axe of Cleaving: When you drop a creature to 0 HP, can make a weapon attack as a bonus action.
Gauntlet of Weapon expertise: Gain proficiency with 3 weapons types.
Gauntlet of Weapon Grand Mastery: You can take -5 on attack rolls to gain +10 damage on a hit.
Falconer goggles: Ignore 1/2 cover and long range penalty.
Crossbow of speed: This weapon loses the loading trait.
X (medium armor) of Comfort: Max dex bonus to AC is 3 instead of 2. Ignore stealth penalty.
Ring of X (elemental type) adept: Ignore resistance to X element and reroll 1-2 on damage rolls.
X (medium of heavy armor) of the Squire: This armor grants proficiency with X armors and shields.
You can even make equipment sets ala Diablo:
Delver's armor: Resistance to traps damage and advantage to saves against trap.
Delver's helm: Advantage to spot traps and secret doors.
Delver's boots: Doesnt not have a penalty when walking at fast pace.
When the Delver's armament is assembled on your person, you can cast Detect Trap, Knock and Arcane Lock once per day each.
etc