Release phrase: Spin
Shikai form: chakram, although the hilt remains. The movement of the chakram is directed by the hilt but the chakram itself it not attached to the hilt
Shikai special ability: Seals the powers of the opponent's zanpakuto but while this power is active, the chakram has to remain stationary and emits a green light. Thus even as the opponent loses their zanpakuto, the shinigami wielding Anahata also can't continue to use it to fight. Anahata's special ability also works against Arrancar zanpakuto.
Release phrase: Rise from the ashes
Shikai form: Summons the legendary king of the birds Fenghuang, which also the eastern phoenix
Shikai special ability: The summoned bird has poison claws and spits out fire from its mouth.
Release phrase: Dance the dance of death
Shikai form: A large Ring Blade 
Shikai special ability: None but the blade would be best in the hands of a Shinigami with high gymnastics skill and a flashy style as the ring blade can be used in all sorts of weird ways, like a hula hoop that cuts the enemy as you dance the hula; or the blade can be flung and caught with your legs as you do a hand stand... just go watch this video .
Bankai form: Wind-and-fire wheels attached to the hand, with both arms covered in metal gauntlets.
Bankai special ability: The wheels get the ability to manipulate wind and fire. Gives bonuses to hoho and hakuda.
Name: Black plague
Release phrase: Spread
Shikai form: Turns the blade of the katana black.
Shikai special ability: If you are cut by the katana, eggs get released into your cut. After a bit the eggs hatch and flesh eating beetles start to consume you from the inside. The only way to stop this is to kill the beetles or kill the eggs before they hatch by applying heat to your wounds or cutting away the wounded area.
Name: Golden Dawn
Release phrase: Come
Shikai form: Golden halberd
Shikai special ability: None. It's just a halberd but believe me you don't want to be cut by it. It hurts!
Release phrase: Mimic
Shikai form: Takes the form of the enemies zanpakuto. If the enemy is a hollow, the blade remains as is but gains the ability of said hollow.
Shikai special ability: mimics the powers of the opponent. In the case of a shinigami's zanpakuto the release phase and the name must also be used. So if the Shinigami releases his/her zanpakuto silently (as is possible if they have bankai) then Nijuushin fails.
Bankai form: The blade of Nijuushin disappears, leaving behind just the hilt, a blinding white mist and a perfect Doppelgänger of the enemy.
Bankai special ability: Creates the perfect Doppelgänger of the enemy.
Once again, this is totally pointless blog post. I just wanted to share my "awesome" (not) zanpakuto ideas.