The Uchiha Clan had the Sharingan which has a lot of different stages:
- Sharingan (Increases power with age/3 commas = maturity)
- Mangekyo Sharingan (Unlock = Kill a close friend/family member) (Blindness over time)
- Time Erase (Kasashi's Mangekyo Sharingan)
- Eternal Mangekyo Sharingan (Perfect vision/Incredible Power)
- Amaterasu (Invincible Fire Attack)
- Tsukuyomi (Illusion Technique)
- Mind Control (Shisui Uchiha 'Mental Genjustu')
- Copying Ability (Endless library of techniques) (See opponents techniques/Mimic opponent)
- Susano'o (Giant Skeleton/Invincible Sword 'Totsuka Blade'/Invincible Shield 'Yata Mirror')
- The Blade and Mirror were found by Itachi, by unknown means - Teleportation
- Intangibility (Madara Uchiha)
- Izanagi (Dream/Illusion Technique)
- Sharingan+Rinnegan Techniques
- Mangekyo/Eternal Mangekyo
And it varies for each user in shape and appearances:
- Sasuke Uchiha - Six-Sided Star Shape (Mangekyo) Six-Sided Cyclone (Eternal)
- Itachi Uchiha - Three-Sided Cyclone
- Kakashi Hatake - Bizarre Three-Sided and Curved Cyclone
- Madara Uchiha - Izuna Uchiha - Stange Opened Circle with Three Squarish-Openings
- Shisui Uchiha - Four Sided Throwing Star
But the Byakugan stays the same and every member has the same one.
So it makes me curious, why doesn't Byakugan have a second stage?