Movement speed/slows

Source	Slow	Duration
Abaddon – Curse of Avernus	10%/15%/20%/25% (30%/40%/50%/60% for Curse)	4
Ancient Apparition – Ice Vortex	15%/20%/25%/30% ( 23%/28%/33%/38%)	16
Ancient Apparition – Chilling Touch	100%	0.5
Ancient Thunderhide – Slam	25%	2 (4 on creeps)
Arc Warden – Flux	20%/30%/40%/50%	6
Arc Warden – Spark Wraith	100%	0.4/0.5/0.6/0.7
Axe – Battle Hunger	12%	12 (or until enemy kills a unit)
Batrider – Sticky Napalm	3%/5%/7%/9% per stack	8
Beastmaster – Primal Roar	60%	3/3.5/4
Boar – Poison	10%/20%/30%/40%	3
Bounty Hunter – Shadow Walk	14%/20%/26%/32%	4
Brewmaster – Cinder Brew	25%	7
Brewmaster – Thunder Clap	25%/35%/45%/55%	4 ( 7) (8 ( 11) on creeps)
Bristleback – Viscous Nasal Goo	20% + 3%/6%/9%/12% per stack	5 (10 on creeps)
Broodmother – Incapacitating Bite	16%/26%/36%/46%	2
Centaur Warrunner – Stampede	100%	1.8
Chaos Knight – Reality Rift	15%/25%/35%/45%	2
Chen – Penitence	18%/24%/30%/36%	5/6/7/8
Crystal Maiden – Crystal Nova	20%/30%/40%/50%	4.5
Crystal Maiden – Freezing Field	30%	1
Dark Seer – Wall of Replica	50%/60%/70%	0.75
Dazzle – Poison Touch	14%/16%/18%/20% ( 54%/56%/58%/60%)	4/5/6/7
Death Prophet – Spirit Siphon	4%/6%/8%/10%	6
Diffusal Blade – Inhibit	100%–20%	4
Dragon Knight – Elder Dragon Form (Frost Breath)	30%	3
Drow Ranger – Frost Arrows	16%/32%/48%/64%	1.5 (7 on creeps)
Dust of Appearance – Reveal	20% (invisible units only)	12
Earth Spirit – Boulder Smash	80% (only when using a Stone Remnant)	1.25/2.5/3.25/4
Echo Sabre – Echo Strike	100%	0.8
Elder Titan – Earth Splitter	30/40/50%	3/4/5 ( 4/5/6)
Enchantress – Enchant	55%	3.75/4.5/5.25/6
Ethereal Blade – Ether Blast	80%	3
Eye of Skadi – Cold Attack	35%	5/2.5 (melee/ranged)
Faceless Void – Time Dilation	14% (for each cooldown frozen)	6/8/10/12
Ghost – Frost Attack	20%	1.5
Grimstroke – Stroke of Fate	50%/60%/70%/80%	1.5
Grimstroke – Soulbind	15%/30%/45%	6/7/8
Gyrocopter – Call Down	30%/60% (first/second missile)	2/4 (first/second missile)
Hellbear Smasher – Thunder Clap	25%	3
Huskar – Life Break	40%/50%/60%	4/5/6
Invoker – Ghost Walk	20%/25%/30%/35%/40%/45%/50% ( /55%), 30%/20%/10% self-slow on levels 1–3	100 (linger duration 2)
Invoker – Ice Wall	20%/40%/60%/80%/100%/120%/140% ( /160%)	3/4.5/6/7.5/9/10.5/12 ( /13.5)
Io – Spirits	20%/40%/60%/80%	0.3
Jakiro – Dual Breath	28%/32%/36%/40%	5
Kunkka – Torrent	35%	3.35/4.1/4.85/5.6 (applied together with a stun)
Leshrac – Lightning Storm	75%	0.4/0.6/0.8/1 ( 3.4/3.6/3.8/4)
Lich – Frost Blast	30%	4
Lich – Frost Shield	35%	0.5
Lich – Chain Frost	65%	2.5
Lich – Freezing Slow	40%	3
Lifestealer – Open Wounds	70%–10%	8
Lion – Mana Drain	20%/24%/28%/32%	5
Magnus – Shockwave	60%	0.75
Magnus – Skewer	25%/30%/35%/40%	3.25
Medusa – Stone Gaze	35%	5/6/7 (only when facing Medusa)
Monkey King – Primal Spring	0%–20%/40%/60%/80%	4
Necrophos – Ghost Shroud	6%/12%/18%/24% ( 26%/32%/38%/44%)	3/3.5/4/4.5 (when in radius)
Night Stalker – Void	50%	1.25 (day), 2.5/3/3.5/4 (night)
Nullifier – Nullify	100%	0.4 (can last up to 5)
Ogre Frostmage – Ice Armor	30% (melee units only)	5
Ogre Magi – Ignite	20%/22%/24%/26%	5/6/7/8
Omniknight – Degen Aura	10%/18%/26%/34% ( 22%/30%/38%/46%)	Indefinite (lingers duration 1)
Orb of Venom – Poison Attack	12%/4% (melee/ranged)	3
Pangolier – Lucky Shot	40%	2/3/4/5
Phantom Assassin – Stifling Dagger	50%	1.75/2.5/3.25/4
Phantom Lancer – Spirit Lance	10%/18%/26%/34%	3.25
Phoenix – Icarus Dive	19%/22%/25%/28%	4
Pudge – Rot	11%/18%/25%/32% ( 23%/30%/37%/44%)	Indefinite
Pugna – Decrepify	30%/40%/50%/60%	3.5 ( 5.5)
Queen of Pain – Shadow Strike	20%/30%/40%/50%–0%	15
Razor – Plasma Field	5%-25%/30%/35%/40%	1.5
Riki – Smoke Screen	8%/12%/16%/20%	6 (linger duration 0.5)
Roshan – Slam	50%	2 (4 on creeps)
Sand King – Caustic Finale	15%/20%/25%/30%	3
Sand King – Epicenter	30%	3
Satyr Banisher – Purge	50%–10%	5
Shadow Demon – Demonic Purge	100%–20%	7
Shadow Fiend – Requiem of Souls	25%	5
Shiva's Guard – Arctic Blast	40%	4
Silencer – Arcane Curse	9%/12%/15%/18%	6 (+5 per ability cast)
Skywrath Mage – Concussive Shot	30%/35%/40%/45%	4
Slardar – Slithereen Crush	20%/25%/30%/35%	4/5/6/7 (applied together with a stun)
Sniper – Shrapnel	15%/20%/25%/30%	10 (linger duration 0.5)
Sniper – Headshot	100%	0.5
Spectre – Spectral Dagger	8%/12%/16%/20% ( 28%/32%/36%/40%)	12
Spiderling – Poison Sting	8%	2 (6 on creeps)
Storm Spirit – Overload	80%	0.6
Templar Assassin – Psionic Trap	30%–60%	5
Terrorblade – Reflection	20%	2.5/3.5/4.5/5.5
Tidehunter – Gush	40%	4
Timbersaw – Chakram	5% (for every 5% of health missing)	Indefinite
Timbersaw – Chakram (Aghanim's Scepter)	5% (for every 5% of health missing)	Indefinite (linger duration 0.5)
Tornado – Tempest	15%	40 (linger duration 0.5)
Treant Protector – Leech Seed	16%/20%/24%/28%	5.25
Troll Warlord – Whirling Axes (Ranged)	40%	2.5/3/3.5/4
Tusk – Tag Team	75%	0.5 (can last up to 5)
Tusk – Walrus PUNCH!	40%	3/4/5
Tusk – Walrus Kick	40%	5
Undying – Flesh Golem	24%/32%/40%	30 (linger duration 0.5)
Undying Zombie – Deathlust	7%	2.5
Ursa – Earthshock	25%/35%/45%/55%	4
Venomancer – Venomous Gale	50%–0%	15
Venomancer – Poison Sting	11%/13%/15%/17% ( 17%/19%/21%/23%)	6/9/12/15
Viper – Poison Attack	25%/30%/35%/40%	3
Viper – Viper Strike	40%/60%/80%–0%	5
Visage – Grave Chill	32%	3/4/5/6
Warlock – Upheaval	7%/14%/21%/28% per second channeled, max of 84%	16 (linger duration 3)
Windranger – Windrun	15%/20%/25%/30% ( 45%/50%/55%/60%)	3/4/5/6 (linger duration 3)
Winter Wyvern – Arctic Burn	22%/28%/34%/40% ( 37%/43%/49%/55%)	5
Winter Wyvern – Splinter Blast	30%	4
Wraith King – Wraithfire Blast	20%	3.1/3.4/3.7/4 ( 4.6/4.9/5.2/5.5) (Applied together with a stun)
Wraith King – Reincarnation	75% ( 0%)	5 ( 0)