All skins based on Lore.

So, I decided to do a list with all the Skins that have directly or indirectly relation to the lore. (WARNING: If you disagree or you think that I missed something, please tell me in the comments below ^_^. Also, a lot of these skins have relation to Alternative Universes eg: Project)

Lets begin!

• Justicar Aatrox: This is how some people view Aatrox (Demacians), not as a bloody Killing-Machine!
• Mecha Aatrox: Mecha,PROJECT,Program and Super Mecha skins share the same universe (speculation).
• Arcade Ahri: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!
• Blood Moon Akali: Akali with that sexy Ionian outfit , she wore it with Shen to represent a theatrical play during the Festival of Fire!
• Unchained Alistar: Possibly Alistar before being captured by the Noxian scums!
• Marauder Alitsar: this skin represents the Magelords' armor during the Rune Wars.
• Blackfrost Anivia: Anivia being corrupted by Lissandra's Dark ice.
• Freljord Ashe: Ashe at her young age of life.
• Queen Ashe: Ashley after being married to Tryndamere for political reasons.
• PROJECT Ashe: Mecha,PROJECT,Program and Super Mecha skins share the same universe.
• Marauder Ashe: this skin represents the Magelords' armor during the Rune Wars.(Owl side in Summoners' Rift)
• Rusty Blitzcrank: Blitz took that heavy damage after fighting with Zaun's troublemakers.
• Arcade Blitzcrank: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!Blitz represents a boss!
• Spirit Fire Brand: A representation of Brand's form before taking control Kegan Rodhe's body (?)
• Program Camille: Battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Battlecast Prime Cho'Gath: Battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.In this reality Cho'Gath is modifiedby Creator Viktor.
• Arcade Corki: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!Corki represents galaga.
• lord Darius: This version of Darius shows him as the Grand general of Noxus. Also, this could be a Version of Darius with his formal outfit.
• Blood Moon Diana: This theme is odd, although Blood Moon Thresh, Kalista, Shen, Akali (and possibly Kennen) have some relation to the lore, a lot of the newest Blood Moon skins (including Diana) don't provide us with Lore material.
• PROJECT Ekko: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Blood Moon Elise: This is probably how Ionian people view Elise (like Thresh or Elise).
• Tango Evelynn: Nothing here, I put it on the list because it hints the relationship between her and Tobias.
• Pulsefire Ezreal: Ezreal getting a sweet update (?)
• Arcade Ezreal: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!
• Debonair Ezreal: This one is pretty interesting. It shows us a good look of what does Piltovians wear during special occasions.
• PROJECT Fiora: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Void Fizz: Fizz being corrupted by the Void? I heard that Nautilus had some relation with the void during his transformation, so this is quite possible to happen!
• Super Galaxy Fizz: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Debonair Galio: (his rework is coming soon <3) that skin shows us a good look of what Piltovians wear.
• Captain Gangplank: this is Gangplank before been torn into pieces along with his ship by Sarah Fortune.
• Steel Legion Garen: This is Garen in an alternative reality where he (along with Lux and some other guys) fights against the technological corruption of Creator Viktor.
• Cutthroaat Graves: Graves with Twisted Fate used to be Bounty Hunters buddies! This is how they looked like!
• Arcade Hecarim: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!
• Void bringer Illaoi: Illaoi corrupted by the Void? Seems pretty unlikely!
• Dragonslayer Jarvan IV: The armor that Jarvan wore while helping Shyvana kill that damn dragon who killed her father.
• Temple Jax: Jax is a simple guy, he loves eggs and wants to defeat the Void creatures that destroyed his homeland: Icathia. This is probably a formal suit Jax wears whenever he doesn't go fishing or duel Fiora!
• Warden Jax: This skin represents the armor that was worn by the Protectorates during the Rune Wars.
• Debonair Jayce: PILTOVIAN CUSTOM!!!
• Full Metal Jayce: This skin is from an alternative reality where Jayce, leads up a group of Rebels (Full Metal Pantheon,Steel legion Garen etc) to defeat Creator Viktor and his armies of battlecast and Mecha creatures!
• Blood Moon Kalista: This is how Ionian People view her.
• Warden Karma: This skin represents the armor that was worn by the Protectorates during the Rune Wars.(Stag Side)
• Pentakill Karthus: Karthus hitting that high notes. He recruited the Pentakill Band so they can bless our ears with Metal music.
• Pre-Void Kassadin: How Kassadin looked before being consumed by the Void. *Harbinger Kassadin: How Kassadin would look if he was fully corrupted by the Void! That means that he would also joined forces with Malzahar!
• High-Command Katarina: Katarina took that promotion and now serves at her Father's rank.
• PROJECT Katarina: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Unmasked Kayle: Kayle without her mask (duh)
• Blood Moon Kennen: Possibly has a relationship with Blood Moon Shen and Akali during the Festival of Fire but nothing is confirmed yet!
• Mecha Kha'Zix: In this alternative reality, Kha'Zix is being augmented by Creator Viktor to help him take over Valoran!
• Super Galaxy Kindred: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Batttlecast Kog'Maw: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Acolyte Lee Sin: This is Lee Sin when he was younger.
• PROJECT Leona: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Iron Solari Leona: Leona in a more appropriate and formal armor for a Solari.
• Program Lissandra: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• PROJECT Lucian: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Spellthief Lux: Lux is almost impossible to beat with magic. This skin, shows Lux on a personal mission, without the supervision from Demacia or from her elder brother, stealing spells and thus, empowering her magic abilities.
• Steel legion Lux: In this reality, Lux and her brother Garen, are trying to defeat Creator Viktor's forces and bring balance to Valoran.
• Elementalist Lux: This is Lux on her final form (maybe?)
• Mecha Malphite: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Shadow prince Malzahar: This is possibly Malzahar before been corrupted by the Void.
• Haunted Maokai: This represents Maokai in case he didn't absorb the holy waters from the blesses isles, allowing the Black Mist to corrupt him.
• Ionia Master Yi: Yi with his traditional Ionian outfit.
• Project Yi: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Captain Fortune: This is Sarah after destroying Gangplank's ship and taking over Bilgewater.
• Arcade Miss Fortune: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!
• Pentakill Mordekasier: Karthus recruited him so he can bless our ears with that sweet Metal Music!
• Exiled Morgana: This represents Morgana before been exiled by the Angel-tribe thingy..?Can't really tell because her lore is outdated.
• Infernal Nasus: In an alternative Universe (actually, in the one that the battlecast take place) Nasus is the one that got locked with Xerath in that tomb.Resulting him going mad providing him with that dope appearance.
• Warden Nautilus: This skin represents the armor that was worn by the Protectorates during the Rune Wars.(Stag Side)
• Pentakill Olaf: Karthus recruited him, now we have Metal Music, simple.
• Marauder Olaf: this skin represents the Magelords' armor during the Rune Wars.
• Full Metal Pantheon: In this Alternative universe, Pantheon is on a team of rebels (lead by Jayce) to defeat Viktor's forces.
• Full Metal Rammus: Same as Pantheon he helps them to defeat the Battlecasts!
• Rune Wars Renekton: This is Renekton before turning into madness by the manipulation of Xerath.
• Redeemed Riven: this could be Riven after the Noxian invasion to Ionia or before, both cases sound interesting.
• Arcade Riven: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!
• Super Galaxy Rumble: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Young Ryze: This represents Ryze when he was younger.He was under the supervision of his Master Tyrus.
• Traditional Sejuani: Again, this skin shows us how Sejuani looked when she was younger.
• Blood Moon Shen: During the Festival of Fire Shen with Akali played a theatrical play wearing the Bloodmoon skins.
• Super Galaxy Shyvana: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Augmented Singed: This could be Singed, after been augmented by Viktor's Research and thus joining the Glorious Evolution.
• Mecha Zero Sion: Desgined by Creator Viktor to bring terror.
• Warden Sivir: This skin represents the armor that was worn by the Protectorates during the Rune Wars.(Stag Side)
• Battlecast Alpha Skarner: Augmented by Creator Viktor.
• Pentakill Sona: Member of the Pentakill Band, Sona provide us with great Metal Music.
• Arcade Sona: Arcade is a theme that is based on an Alternative Universe, it is a goofier and a full of references variant of Champions!
• Divine Soraka: This is Soraka before been transformed into the purple healing creature we know (and love)
• Tyrant Swain: This is actually how Swain should look like, after been elected as High Commander of Noxus.
• Justicar Syndra: This represents Syndra before been corrupted by her Powers.
• Omega Squad Teemo: this skin shows us the "Dark Side" Teemo hides inside him.
• Blood Moon Thresh: This is how Ionians view him.
• King Tryndamere: This represents Tryndamere after his marriage with Ashley.
• Demonblade Tryndamere: Aatrox killed Tryndamere and revived him with that form. Now his rage has unbelievable powers.
• Cutpurse Twisted Fate: Bounty Hunter Buddies with Graves, long ago their separation and betrayal.
• Shockblade Zed: Probably Zed before his devotion to the Shadows.
• PROJECT Zed: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Special Weapon Zac: This is actually how Zac was suppose to look like, as a mindless weapon created by the Zaun scientists.
• Full Machine Viktor: Viktor's Goal to fully augment himself.
• Prototype Viktor: This is him before fully augment himself.
• Creator Viktor: He won Jayce and now has the red crystal to succeed to his goals.In this alternative reality, he creates: The battlecast, Mecha Zero Sion and possibly the PROJECT champions!
• Battlecast Xerath: Still part of the Battlecast line, but extremely outdated skin!
• Battlecast Vel'Koz: battlecast,Mecha,PROJECT,Program and Super Galaxy skins share the same universe.
• Arclight Varus: This skin represents Varus before been corrupted by that temple.
• Spirit Guard Udur: This is actually how Udyr should look like after Lee Sin brought him from Freljord to Ionia to unlock his true potential!

And here it is.....pheww.....if you spot any grammar or spelling mistakes please let me know! Also, if you think that I missed any skin, again write it in the comments! Sorry for not explaining in detail some skins. i hope you have a great day!