Final Fantasy

Final Fantasy games, being and RPG often include Low Level challenges and Solo Character Runs, but also quite often have restriction on mechanics

Final Fantasy
Final Fantasy challenges include:
 * Single Class Run
 * Fighter
 * Thief
 * Monk
 * Red Mage
 * Black Mage
 * White Mage
 * Solo Characters Run
 * Fighter
 * Thief
 * Monk
 * Red Mage
 * Black Mage
 * White Mage

Final Fantasy III
Final Fantasy III challenges include:
 * Solo Character Run
 * No Class Change
 * Solo Character/No Class Change

Final Fantasy IV
Final Fantasy IV challenges include:
 * Solo Cecil Challenge

Final Fantasy V
Final Fantasy V challenges include:
 * Single Class Run
 * No Class Change
 * Low Level Run

Final Fantasy VI
Final Fantasy VI challenges include:
 * CES Challenge
 * Fewest Steps Challenge
 * Speed Run

Final Fantasy VII
Final Fantasy VII challenges include:
 * Command Only Challenge
 * Enemy Skills Only Challenge
 * Materia Only
 * Initial Equipment
 * No Materia No Accessories (IENMNA)
 * No Accessories, No Escape, No Physical Attacks, No Limit Breaks, Command Materia Only (IENANENPANLBCMO)
 * Low Level
 * No Materia (LLNM)
 * Initial Equipment, No Accessories (LLNMIENA)
 * No Items, Initial Equipment, No Accessories (LLNIIENA)
 * Command Materia Only (LLNIIENACMO)

Final Fantasy VIII
Final Fantasy VIII challenges include:
 * No
 * Junction Challenge
 * Level Challenge
 * Guardian Force Challenge
 * Leveling Challenge

Final Fantasy IX
Final Fantasy IX challenges include:
 * Attack/Item Only Challenge
 * Beatrix Only Challenge
 * Blank/Marcus/Cinna Challenge
 * Excalibur II Challenge
 * Excalibur II Perfect Game Challenge
 * Level 1 Game
 * No
 * Equipment Challenge
 * Healing/Money
 * Solo Character Challenges
 * Amarant
 * Eiko
 * Freya
 * Garnet
 * Quina
 * Steiner
 * Vivi
 * Zidane

Final Fantasy X

 * No
 * Sphere Grid (NSG)
 * Initial Equipment (NSGIE)
 * Summon/Customize (NSGNSNC)
 * Summon/Overdrive (NSGNSNO)
 * Customize/Escape/No Encounters/Blitzball (NSGNSNONCNENNENBB)
 * Solo Character
 * Auron
 * Kimahri
 * Lulu
 * Rikku
 * Tidus
 * No Customize
 * Wakka
 * Yuna