Udyr....oh wait.

Keep coming up with too many ideas xD

Jayce's T - Wired Up / Distortion
Hammer Stance: Jayce swings his hammer around him, dealing 90/140/180/230/270 magic damage (+.6 AP) to all enemies around him, and slowing them for 25/30/35/40/45% for 3 seconds. Deals half damage to enemy minions and monsters.
Cannon Stance: Jayce fires a beam of energy, dealing 65/105/140/195/235 magic damage (+4 AD) and stunning the first target it hits. If the target is a champion, the damage is increased by 50%.
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Twisted Fate's T - Raise the Stakes
Twisted Fate tosses out a handful of cards at an enemy, dealing 80/120/180/250/280 magic damage (+.8AP) (+.9 AD modifier) to the target and rooting them for 1.5 seconds.
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Riven's T - Path of the Fallen
Passive: Riven excels at solo fighting, gaining 20/25/30/35/40 armor and magic resistance as long as she is isolated from nearby allied champions.
Active: Riven doubles her passive bonus for 10 seconds. This effect lasts even if allies are nearby.

I know this is already in the game but...

Teemo's T is a global taunt that makes people run to the closest shroom.

Nidalee's T - Beastly Instincts(Human and Cougar) - Nidalee empowers her next ability. Costs: 90/110/130/150/170 mana Cooldown: 15 seconds

Empowered Effects:
Q Human - Also applies Grievious Wounds if it hits for 5 seconds
Cougar - Slows the target.

W Human - AoE Circle of Traps
Cougar - Jumps double distance

E Human - Also provides bonus 10/15/20/25/30 Attack Damage for the same duration as Attack Speed steroid
Cougar - Changes abliity to Fury Swipes(pokemon LOL) - Does damage in a cone. Champions hit are slowed by 70% and take double damage

If the bonus isn't used in the duration then Nidalee gets her mana refunded and the cooldown is 1 second lower.

Just thought of another one for Varus

Varus T - Agonizer Arrow - Varus's next attack does bonus 50/100/150/200/250 DoT (procs Blight)

Kayle- Holy Light

Blinds all enemies in a cone dealing magic damage with a 0.3 AP scaling (rank ups reduce CD and increases magic damage)

Lee Sin- Concentration/Force of the Dragon
Lee Sin halts to channel for 2 seconds, ignoring 20% of all damage, on second activation charges forward for 600 units of range while dealing 80/120/160/200/240(+1:1.5 Bonus AD)
champions who are caught in the path are knocked aside and slowed by 20/30/40/50/60% for 2 seconds
costs 60/40 energy and has 10 second CD

Vladimere- Empower the tides 15 sec CD no cost
Vladimere consumes current stacks of tides of blood, healing 10/20/30/40/50(+1:0.3AP)per stack while empowering his next ability with increased benefits depending on the amount of stacks
q: increases damage and heal by 2/4/6/8% depending on the number of stacks
w: increases duration of pool by .25/.5/.75/1 depending on the number of stacks
e: heals for all damage dealt and increases damage by 2/4/6/8% depending of the number of stacks

Darius : Darius uses his axe to grab an enemy champion and fling them over Darius' head and behind him, damaging the target in the process. However, for the next 2 seconds Darius' attack speed is halfed and silenced due to the amount of sheer strength he used to fling his target into the air.

Cooldown : 40 / 35 / 35 / 30 / 30 / 25

Mana Cost : 80 / 80 / 80 / 80 / 80

Damage Dealt : 5 / 10 / 15 / 20 / 25 True damage + 110% of attack damage (not true damage)

malzahar blasts the enemy with a small beam of void energy