Banner of the war master

this banner is made up of the hides of beasts, or bits the banners of your foes, that your "warband" or "party" have felled
each new rarity of banner gets the powers of the previous tier.
Common - all other allied creatures within 30ft of you, get a +1 to their attack and damage rolls and if those attacks are weapon attacks they are considered magical for getting through resistances and immunities (this extra +1 applies to both spell attack and damage not just weapon attacks)

Uncommon - all other allied creatures within 60ft of you: when they hit with a weapon attack they deal a extra 1d4 damage

Rare: all other allied creatures with in 90ft of you get an additional +1 (for a total of a +2) to their attack and damage rolls, as a action you can command all those under the effect of your banner to make one weapon attack or cast a cantrip as a reaction (this extra +2 applies to both spell attack and damage not just weapon attacks)

Very Rare: all other allied creatures with in 120 ft: may add a extra 2d6 (instead of the 1d4 from the uncommon banner) to their damage, any creature you have commanded to attack has advantage to attack the targeted creature you have marked for them to attack

legendary: all other allied creatures who can see your war-banner and hear your commands are granted an additional +1 (for a total of a +3) to their attack and damage rolls, and add a extra +3 to all of their saves, as well as a extra +3 to their ac, the damage bonus increases to 3d8 (instead of 2d6 from the V. Rare banner) damage and their crit range is increased by 1 while attacking the creature you have commanded them to attack (if they would normally only crit on a natural 20, they instead crit on a 19 or a 20, if they crit on a natural 19+ they now crit on a natural 18+ on the dice, etc, etc)

Notes: warmaster (someone who has proven them selves to be a leader of others on the battlefield)