Add overpowered utility to moves. (i have lots of examples)
Sion - R: When Sion hits a wall, he bounces off and continues in a direction perpendicular to the wall. This allows for stupid playmaking and creates terror for the enemy team's ability to predict his direction. Fizz - W: Can jump a third time to refresh untargetable duration, but deals no damage. *Vayne - Q: ** After shooting, Q's cooldown is refreshed. Warwick - R: If the ability kills the target, the ult jumps to a nearby champion. Ezreal - Q: If the Q hits a target, the projectile will continue traveling for one second. This can stack multiple times on one Q, potentially riding it along a minion wave for huge range. (Cooldowns are reduced by 1 second for each target hit). Lucian - R: APPLIES ON-HIT EFFECTS INCLUDING RUNAAN'S HURRICANE Karthus - Q: * If a target is hit, another Q is casted on their curent location. If the target remains in one place, Qs can be stacked infinitely for rapid damage. Gragas/Sejuani - R: If all 5 enemy champions are hit, refreshes R's cooldown. **Gnar - E: ** When bouncing off an enemy, Gnar will land at the cursor's location rather than forward. Singed - Q: Poison trails don't go away. Unless Singed dies. **Singed - W: ** Adhesive doesn't go away. Unless Singed dies. **Singed - R: ** Buff doesn't go away unless Singed dies. And it can be stacked. Lee Sin - Q: When pressing Q again to dash to the target, instead, Lee Sin will follow the cursor for 5 seconds. The first champion he hits will take the damage. This allows Lee Sin another stupid escape ability and even more ridiculous mobility.
Ok now I'm getting crazy.
Think of something that adds a new element to the gameplay outside of making the move do more damage. Instead of making a move instant kill, make an element that forces people to look out for it. It can still be overpowered though.
OK go
immobilizes champions he grabs
Has no limit on the number of turrets on the field. Turrets remain active no matter where Heimerdinger is.
whenever a enemy champion touches your ice wall they get stunned and slowed
passive cooldown is reduced by 2 every time you auto
after pool's duration is over you knock enemy's that are still standing in it into the air
YOU GET A SILENCE 
YOU GET A SILENCE
EVERYONE GETS A SILENCE
W: Soldiers can throw spear in a 550 radius around them at 85% of your normal attack speed, and the thrown attacks do not piece targets, can still stab. Soldiers have unit collision for everyone but Azir
E: Teleports to target soldier and sends target soldier along a path to original location, knocking up all targets along the path and granting Azir a shield based off the number of targets hit
R: Soldiers can be commanded to move by reactivating R, for two additional repositions. R also increases in duration by 4 seconds for every enemy champion hit, and bumped after the initial cast
Q: No CD, no mana cost
Q: Balls now last indefinitely, until Syndra dies or casts an ability to manipulate them
W: Can now be double cast to cause target ball to deal Q and W damage in an area around it (no slow), without moving the ball
E: Balls multiple on contact with terrain, sending one through the terrain and another on a path that the ball would should it have bounced (hits wall coming from left at 30 degrees, bounces off and goes to the right at a 30 degree angle)
R: Balls ricochet off target damaging enemies in an area around the initial target.
Ball has unlimited tether range
Q: much larger cast radius, no longer reduces in damage for more target hit
E: reflects damage inflicted to shielded target
E: Charm pierces minions and will only stop once a champion is struck or it reaches max range
R: Charge system like Akali R, new charges are generated periodically, on kill/assist and every time Ahri uses a passive enhanced spell
W: Reactivate Foxfire to throw them to a targeted area from which they will seek targets which enter their range, Ahri can have 3 fox fire rings active at once, plus one on herself
Passive: Q strike does double damage and stuns, W causes all damage target causes in the next 1 second to heal instead of harm, E 99% slow and effect is AoE (TF red card style)
E: Activate for bonus damage on next AA, and to grant a bonus effect to your next Q or W. (Q throws 6 cards, blue card recovers more mana & drains some of theirs, Gold card blinds targets around the stunned target, and stuns for 2.5 seconds, Red Card Snares, then a move speed slow for 3 second after snare ends)
Remove from game
Q: Can heal herself by getting a bulls eye with her Q on herself
E: Restores mana to Soraka and allies in an area around her should a target be snared
Delete
Q: No delay, leaves an area behind for 3 seconds that will cause any seeds placed there to become thorn spitters
E: Hits whole area at once like a Xerath Q, same field effect as the Q
W: Drops 2 seeds at once, unlimited seed storage, seeds grant vision in an area around them again
R: Snares targets hit by damage, damage starts at outside and comes inwards
Passive: No limit as to how many stacks of passive you can apply to an enemy champion, duration of passive has been increased from 3 seconds to 30 minutes.
Switching stances regenerates 58 HP and 24 Mana over 2 seconds
Feast (R): now heals Cho'Gath for the damage dealt and obvi can refresh if used to kill enemy champ.
His Ult has a set # of hits it can proc. Base number is 20. Every enemy hit with his ult adds 2 hits each time they are hit. He only runs out of hits when the number reaches 0. damage increases the longer his ult goes. SPIINNY WINNY
