A cool way in which pvp, pve and crafting elements can be introduced to the game is through world events.
These events could have an inciting incident, which is activated by a player interacting with a strange relic which may or may not be visible at a distance depending on the nature of the relic.
-If the relic is not found within a game month it is reset to a new location during server down time.The player who finds the relic would be the first to see or experience the content associated with the world event. They may have to battle some new monster and if they win they gain a non craftable item or recipe from a set associated with the world event or become exposed to some toxin and need to find certain reagents, one of which is only found relatively near the relic or the relic somehow guides them to it, if they located the reagent the could recieve an increase to a certain stat and if not a decrease to another.
After the inciting incident, monsters and other content associated with the world event will begin appearing all around the map. After a certain amount of the recipes items and materials associated with the world event have been gathered by the player population the whole thing would end with a large battle involving a large portion of the active player base.
Much of the content associated with the world event will not be attainable in other ways. When the world event ends thats it for those recipe sets, etc. But have no fear it wont be long until another world event with new recipes begins.
An example event could begin with a UFO falling from the sky at night. the crash sight can be reach and thats starts off the inciting incident. Aliens could appear and need to be killed or an alien virus could infect animals and make them mutate in a special way.
The whole thing could end with a large battle against a number of aliens of different strengths.
It would add PVP as people would fight to be able to get the rare stuff associated with the world events