Fifteen Blows (Five Duelist Styles)

 I couldn't resist. Required reading, Loch's excellent Duelist - a fighter that's actually kinda fun.

A Duelist's Halo
Art By Konstantin Vavilov

Ψ - Mercy
The style of the warrior nuns on the Northern frontier, where the sun bleaches all. Requires a blunt weapon.
You might have learned it from one of their fold, or in a near-death experience

1. Technique: Liturgical Waltz - When you would make two successful attacks on a target, you may shove them up to 20' for free.
2. Stance: Divine Repose - Brace your arms in prayer and fall to your knees. You cannot cause any harm to others in any way and you move at a crawl. But you cannot die and you cannot be dismembered.
3. Technique: Make Them See God - When you could riposte, you can instead make the opponent go into Divine Repose for a round by beating them into that position.
4. Stance: Deathtrap Enlightenment - Your eyes glow a yellow weirdlight. Murderers of the first degree cannot make eye contact with you. Cursed items quiver under your gaze.

Ψ - Hadal
The style of unknowable things come to rise from the ocean and cynic's nightmares.
You might have learned it from an indescribable fish in your dreams, or etched on the ocean floor.

1. Technique: We All Float Down Here - Upon a successful attack, you may change the opponent's gravity. They move and fight as if they were swimming in water. Fighters get a save.
2. Technique: Abyss On Earth - Forgo one of your attacks to vomit a vantablack fog. It covers a 20' by 20' area and lingers for 3 rounds. It is impossible by any means mundane or magical to see through it or dispel it.
3. Stance: Flight Of The Fish - If in darkness, you can move in the air as if you were swimming in water.
4. Stance: Trench Fighting - Your extra AC from panache isn't lost when you're submerged in water.

Ψ - School Of Flight
The style of the Students of Flight in their fortress-academy high in the mountains.
You might have learned it from the lessons of the school, or in the entrails of a roc.

1. Technique: Rising Action - When you would riposte, you instead launch yourself off the opponent's weapon up to 20' in the air.
2. Technique: Falling Action - If you are above someone's head, you can make an extra attack with advantage for free.
3. Stance: Airborne Fighting - Your extra AC from panache isn't lost when you're in air. You always fall on your feet and take no damage from falls you prepared for.
4. Stance: Stolen Flight - You can jump up to 10' in the air given you have an arm's length of space to move.

Ψ - Ultraviolent
The style of imperceptible light. Needless to say, its students are elusive.
You might have learned it from an invisible mentor, or on a blank notebook reeking of lemon juice.

1. Technique: Blinding Blood - When you would take damage, your wounds bleed a strong purple weirdlight. Everybody who can see you hurt must make a save or be blinded.
2. Technique: Speed Of Light - If you can see a strong light source you can teleport on top of it in the blink of an eye. Using this to teleport to the sun is an inadvisable, but possible decision.
3. Stance: UV Cloak - Your body becomes invisible. Your equipment does not benefit from this invisibility.
4. Stance: Light's Witness - You can see invisible foes. They glow a strange fluorescent pale and have trailing afterimages.

Ψ - Ook
The style of the primates in the West whose weaponry consists of sticks and stones. Requires a rock.
You might have learned it over tea by a wise orangutan chieftain, or by bonding with your own special rock in a way incomprehensible to others.

1. Technique: Skipping Stones - You can make melee attacks on anybody you see by skipping your stone across their heads. 
2. Technique: OOK OOK AAH - If you deal max damage, you may disable the opponent's ability to communicate in anything but ooks, aahs, and eeks.
3. Stance: Rollout - As long as you are rolling in one direction, you cannot be stopped or moved against your will.
4. Stance: Primal Respect - Take a posture ridiculous to civilized folk but revered by animals. Animals will not attack you unless you have attacked them first. If you are hostile to them, you are the sole focus of their attention.