Companion wheel
Companion perks
Weapon mods
hardcoe mode
More quests
New factions
Gambling
Traits
Binoculars
Night/Thermal vision
Nightkins
Snow
More Freindly Super-Mutants
More than twice the guns
More joinable factions
Reputation
New drugs
Repair kits
Doctors bags
Unique speach options for low intellegence characters.
Crafting
Poison/Medicine making
Ammo crafting
Disguises
180 quests
Ability to Play-Through as a pacifist
Ability to kill every person in-game except for one.
Iron Sights
Non-Lethal ammo types
Ammo Type Switching
Faction ranking
Advanced power armor
Deeper Main Quest
More choices/endings
Electricity
hokers/Strippers
Stregnth/skill requirments for weapons
More Currencies
Courier Missions
Higher level cap
Vegetation
Perks every 2 levels
Perk that allows you to repair armour with another piece of armour SIMLIAR to your armour (Power Armour repaired with Metal Raider Armour) (Duster repaired with Long Coat).... not sure if there is a "Long Coat" in game, but that is an example. Metal to metal... leather to leather... cloth to cloth
If there is anything I've forgotton please tell me and I will add it.