Big ol' List of Skin Concepts/Ideas

Traditional (every reworked champion)
Master Chef Braum
Grill Master Ornn
Fast Food Manager Azir
Golfer Jhin
Dunkmaster Illaoi
Dunkmaster Sett
Dunkmaster Volibear
Touchdown Garen
Cheerleader Lux
Cheerleader Katarina
Dodgeball Syndra
Farmer Nasus
Gardener Yorick
Reaper Nasus
Reaper Kayn
Ravenborn Swain
Arachnoid Illaoi
Arachnoid Malzahar
Trick or Treat Bard
Trick or Treat Zoe
Haunted/Pumpkinhead Ivern
Haunting Xerath
Pumpkin Bomber Ziggs
Pumpkin King Urgot
Pumpkin Priestess Illaoi
Headless Jarvan IV
Headless Thresh
Boneyard Urgot
Undertaker Braum
Bewitching Sona
Bewitching Lulu
Bewitching Yuumi
Bewitching Syndra
Bewitching Diana
Bewitching/Count Quinn
Count Swain
Jhin Helsing
Pool Party Sivir
Pool Party Yorick
Omega Squad Corki
Harlequin Poppy
Heartseeker(s?) Kindred
Heartseeker Kalista
Heartseeker Akali
High Noon Graves
High Noon Evelynn
High Noon Senna
High Noon Karthus
High Noon Samira
High Noon Yone
Pentakill Sion (rhythm guitar)
Roadie Braum
The Baron Pit Jhin (piano/trombone/vocals)
The Baron Pit Draven (drums)
The Baron Pit Morgana (vocals)
The Baron Pit Bard (saxophone)
The Baron Pit Taliyah (tap dance/vocals)
The Baron Pit Jax (bass)
Dragonslayer (Dragon Fist?) Vi
Dragon Trainer Kled
Dragon Trainer Fizz
Dragon Princess Cassiopeia
Firecracker Aurelion Sol
Firecracker Ziggs
Warring Kingdoms Swain
Spirit Blossom Jhin
Cosmic Angel Kayle
Dark Star Morgana
Dark Star Urgot
Dark Star Tahm Kench
Dark Star Fiddlesticks
Dark Star/Cosmic Zilean
Void Bringer Yorick
Void Bringer Zyra
Barmaid Poppy
French Maid Poppy
French Maid Soraka
French Maid Janna
French Maid Camille
French Maid Ahri
Butler Jhin
Demon Quinn
Demon Shaco
Arcade Braum
Battle/Final Boss Mordekaiser
Battle Boss Aurelion Sol
Battlecast Blitzcrank
Battlecast Rek'Sai
Battlecast Hecarim
Bladecraft/Full Metal Elise
Dark Candy Kayn
Santa/Old Saint Ornn
Festive Ivern
Festive Sion
Grinch Trundle
Snow Day/Winter Wonder Camille
Snow Day Yorick
Elderwood Illaoi
Elderwood Kindred
Old God Thresh
Eclipse Diana
Emerald Taliyah
Volcanic Taliyah
Volcanic Anivia
Empress Sivir
Sewn Chaos Kalista
Gatekeeper Illaoi
Gatekeeper Karma
Bartender Singed
Blood Moon Lissandra
Blood Moon Warwick
Blood Moon Cassiopeia
Blood Moon Zed
Master Arcanist Ekko
Master Arcanist Heimerdinger
Star Guardian Caitlyn
Star Guardian Taliyah
Professor Taric
Professor Zilean
Shipwreck Urgot
Rum Runner/Bilgewater Gragas
Deep Sea Vel'Koz
Deep Sea Aurelion Sol
Deep Sea Rek'Sai
Deep Sea/Dark Waters Zyra
Dark Waters Karthus
Minstrel/Bard Sona
God Fist Sett
Crime City Urgot
Crime City Camille
Crime City Twisted Fate
Crime City Gangplank
Marauder Sion
Tango Xayah
Tango Rakan
Vandal Vi
Vandal Pyke
Vandal/Road Warrior Jinx
Queen Sejuani
Queen Lissandra
Sugar Rush Zac
Beekeeper Lulu
Beekeeper Yorick
Bayou Renekton
Tahm Kench in Wonderland (cheshire cat)
Hextech Viktor
Chemtech Jayce
Guardian Of The Sands/Risen Yorick
Surprise Party Rengar
Urfgot
Definitely Not-ilus
Traffic Bard
Reverse Teemo