Nicknames, you shall ecounter bunch of them. The nickname is based off who they were, and not their past self.
Veyrl de Valens : Saintess, Nun, Mad Saintess, Silver Mare (you get the point)
Cidiem Tempest : Young Mare, Cyan Mare, Lost One ect
Stardust Falls : Wierd Genius, Yellow madmare, ect
Twilight Sparkle : Twi, Antisocial purple blob, Sunbutt Pupil, Maniac of Ancient Times, ect
Twilight Sparkle[Alternate] : Alterlight, False Princess, Failing one, Unstable Purple Blob, The Host, Power Source, ect
TipStir? : Green Mare, Captain Garrison, Lucky bastard, ect
Pinkamena Dianne Pie : Pinkie Pie, Pink mare, Party Planner, ect
Pinkamena Dianne Pie[Alternate] : Alter Pie, Bland Pink Blob, Plain Pink Clay, ect
Rarity : Purple head, Boutique Host, The Designer, ect
Rarity[Alternate] : Alterity, Mare in black, Spare puppet, Night creature, Not a Pony, ect
Rainbow Dash : Rainbow head, Dashie, Star of The Show, Speed, Wonderbolts Candidate, ect
Rainbow Dash[Alternate] : Alterdash, Rainbow Head, Rein, Rain, Rainbow, Conjurer, ect
Applejack : Jack, Mother figure, Cowgals, Stubborn me, Farm Keeper, ect
Applejack[Alternate] : ALterjack, Fount of Knowledge, IDIOT, Resoluted, Useless Dimwit, Brain, Brian, ect
Fluttershy : Shy ball, Stare Master, Eye of Death, Nature caretaker, ect
Fluttershy[Alternate] : Altershy, The Butcher, Silent Butcher, Silent one, The one Who Silent, Jeff Lover, Garrison Leader, Ranger Leader, Merciful Sentence, ect
Celestia : Foul Creature, Failed Queen, SunButt, Great Scholar, Starswirl Pupil, Old Mare, Dethroned Princess, ect
Luna : Nightmare Moon, Queen of new Dawn, Sweet Dreams, Worthy Ruler, Competent Worker, Starswirl Pupil, The one Who realise, ect
Discord : Bringer of Chaos, Choosen be Chaos, Draconequus, Creature of Deceit, ect
??? : Good kid, Bringer of Hope, Quickdraw, Puny, ect
??? : 4 tune teller, Bringer of Hope, Pioneer of Change, Tiny, ect
??? : Selfish Prince, Bringer of Hope, Ace Card, Wasted, ect
SnowDrop : The Frost Queen, The Impossible, Empty Vessel, Freed Slave, Dragon Plaything, ect
Laufenas : Her Majesty, Laufen, Empress of The Universe, Old horse, Death house knocker, Fool, ect
Laufenas[Clone] : Her majesty, My Daughter, Grand Regent, Old Mare, Blind Sage, Cold, ect
Erika : Princess of the Empire, Empire representative, Brave Fool, Griefing one, ect
????? : End of the Fic, Avatar of Chaos, Stand above Fan Fiction, Fiction Embracer, Misunderstands one, Real threat, The Winner, ect
???? : The Goat, Saviour, Maggot, Endless, ect
??? : Red Deer, Radio Mouth, Nothing, Fate- To- Die, ect