A first draft of some ideas. I'll probably throw these onto my blog next week after a second glance or two.
Hand Wraps of the Inferno
Weapon (unarmed strike), rare
These long strips of loosely woven silk cloth appear pale yellow in hue but subtly shift to shades of orange and red when wrapped around the hands and wrists.
While wearing these hand wraps, you gain a +1 bonus to attack and damage rolls with unarmed strikes that use your fists.
Additionally. when you slam your fists together, you can choose to ignite the hand wraps, wreathing your fists in fire. This fire does no damage to your hands or arms, but targets hit by unarmed strikes with your hands take an extra 1d6 fire damage. The flames last for 1 minute or until you choose to extinguish the flames as a bonus action. Once used, this property cannot be used again until the following dawn.
Bands of the Tiger
Weapon (unarmed strike), uncommon
These metal rings are made of solid bronze, and appear worn, dented, and scuffed. While the rings are loose, when the wearer makes a fist the rings pull together, acting as a solid piece of metal. The rings are found in sets of four, but there are occasionally paired sets with eight rings.
While wearing these rings you gain a +1 bonus to attack and damage rolls with unarmed strikes that use that fist, and your unarmed attacks use a d4 for damage.
As a bonus action, you can cause the rings to produce either small spikes or blades. This changes the damage type of your unarmed strikes to piercing or slashing, chosen when the item is activated. If wearing two sets of rings, the rings change at the same time, but need not be the same damage type.
Ring of Forceful Striking
Weapon (unarmed strike), rare (requires attunement)
Forged of heavy platinum, this ring is adorned with a stylized fist.
While wearing this ring you gain a +1 bonus to attack and damage rolls with unarmed strikes.
The ring has 12 charges. You can expend a charge while making an unarmed attack to increase your reach with this attack by 5 feet, and this attack deals force damage. The ring regains 1d4+5 expended charges daily at dawn.
Encircling Blades
Weapon (dagger), uncommon
This dagger has a wide, flat blade. When placed over the knuckles the blade curves, wrapping around the hand. While the weapon encircles the hand, it loses its edge and appears as a single wide band of metal.
You gain a +1 bonus to attack and damage rolls with this dagger, including unarmed strikes while worn around the hand. While the dagger is wrapped around your hand, your unarmed strikes with that fist use a d4 for damage.
Rope Arm Wrap
Weapon (unarmed strike), rare
This short length of hemp rope coils around the hands and forearms.
You gain a +1 bonus to attack and damage rolls with unarmed strikes with the first encircled by the cord. When you hit with an unarmed strike using this weapon, as a bonus action you can choose to have the rope uncoil from you arm, wrapping around the the target grappling them (escape DC 12 + your proficiency bonus). On your turn, as a bonus action you can end the grapple and return the rope to your arm.