Instant effect
Increase Cooldown
Increase Cooldown is the game's own name for this effect on the battle screen. The game gives no separate description for it.
Champions with it
47 champions have a skill with a Increase Cooldown effect, according to the effect lines in the game data. This lists who has it and on which skill, not how strong it is or how often it happens: values and chances are on each champion's page.
Adjudicator Penalize
Akoth the Seared Pyretic Release
Alice the Wanderer Clockwork Cyclone
Alika Disorient
Arbalester Lethargy
Armanz the Magnificent Master of Ceremonies [P]; Wyrd Blade
Basher Stinging Blast
Bloodgorged Raging Beast
Conellia Surprising Swiftness
Elegaius Dead Stop (all enemies)
Emic Trunkheart Entanglement [P]
Exemplar High Stance
Fyna, Blade of Aravia Sword Through Time
Gharol Bloodmaul Foecrusher
Ginro the Stork Plunging Beak
Hansel Witchhunter Baneful Burst
Harvester Temporal Burst
Hellfang Tear
Hierophant Lazarius Overwhelming Power [P] (all enemies)
Hurler Pin Down
Kerin the Harvester Threshmaster
Komidus Darksmile Thief of Joy
Lord Entertainer Fabian Spectral Flourish
Magekiller Harry
Miyoko, Flower of Yakai Murderous Slice; Seductive Saboteur (all enemies)
Night Queen Krixia Deathly Apparition
Orynyx Mindcrawler Mindcrawler (all enemies)
Osgrun the Defiler Obsidian Blade
Pathfinder Cait Untraceable
Raf-Matab Elderspear
Ramantu Drakesblood Psychic Overload
Sabrael the Distant Sneer of Disdain
Sanguine Maria Sanguine Fissure (all enemies)
Sinesha Vaporize
Talenna Soulseer Quell The Darkness
Tekteon Fissureflesh Volcanic Presence
Terrorbeast Painful Bite
Trugorr Leave Them Gutted
Tuhak the Wanderer Unfair Fight
Ursine Ironhide Confounding Crush; Ursine Brutality [P]
Venalicia Thrallmother Mother Knows Best (all enemies)
Vildrax Swarm of Horrors
Vogoth Eerie Presence [P]
Warlord Orcish Rituals
Wight King Narses Corruption Scepter
Yumeko Dance of Time (all enemies)
Zephyr Sniper Suppressive Fire
Taken from the game data and not tested in battle here. See Data quality.