Make your own.
My game started out in an area known as Five Point. It's five villages set up like a pentagram. Due to the ridiculously high magic of the area, it takes 8 hours to get to any of them. They each have roads leading to the two next to them, plus one to a fountain in the very middle. The fountain is indestructible, and the forest around it is cut down yearly for a festival. After 3 days, the woods grow back. The festival is a celebration of the holding off of the Orc attacks. These happen every year at the same time.
When my campaign started, the festival was 3 weeks away. The strange thing was that the Orcs hadn't attacked yet. Not only that, but there were refugees who had started streaming into the city. Apparently, the Orcs had switched from raiding to slaughtering. They were looking for something.
A few small groups were sent from the villages in different directions between West and North. They were scouting.
The main idea for the rest of it is that there are Changelings who are manipulating the Orcs into finding them some special artifacts. The Changelings are worships of Mordain. He's a Wizard in the Eberron setting. WotC had an article about Mordain's Forest of Flesh. For my world, Mordain was an ancient Wizard who was seen as too dangerous. He was a fan of mixing things together that shouldn't be mixed together. When they tried to kill him, they could never succeed. He was like Russia's Rasputin, only worse. He had transcended being human. In the end, numerous spellcasters got together and shunted him to a pocket dimension between the Shadowfell and the Far Realm. While most people know him as Mordain the Fleshweaver, the Changelings refer to him as Mordain the Maker or Mordain the Healer. As they find the artifacts, which have an elemental theme, they perform a ritual and change. I've had them changing into Genasi.
Where Five Point now is, there stood Mordain's Spire. When the Giant Myrdoon unleashed his fury upon it, he destroyed part of the area. It also created a number of artifacts and some crazy, uncontrolled magic. The magic was harnessed and used to create the fountain and magical woods between the towns. It also causes the area out to about a day and a half in every direction to be peaceful. There is a general calming effect on everyone in the area. All of the races get along great and nobody does anything wrong. Soldiers and guards are still trained because of the occasional wild animal, as well as the Orcs and their minions. The magic also limits the power of the people in the area. There is nobody above 6th level in all of Five Point. It means that there can never be another Mordain.
As the artifacts are brought together, the area around them changes. The enemies have a few of the artifacts, and they actually managed to resurrect the Forest of Flesh. These are the Spellscarred areas. (I really liked that stuff from the FRPG.) If the players get all of them, they will merge the artifacts with the fountain and perform a ritual to make the happy-magic of the last 1000 years permanent, and it will become a lot larger than it currently is. If the enemies succeed, though, the Forest of Flesh and the Spire returns, and Mordain will once again walk the land. This time, though, he's had a thousand years to absorb the darkness of the Shadowfell and the insanity of the Far Realm.
Most of the campaign has been made up as I go. I literally do not prepare. It's worked out really well. I've been able to add to the story as we've gone through. What's funny is that I only had 2 players for a while. One was an Elven Warlock with the Dark Pact and now a Spellscar. The other is a Dragonborn Paladin who now has a bit of Barbarian. I have made ample use of the idea of using interesting things and doing what I want.
At one point, in the Spellscarred Forest, the Warlock was fighting with a massive snake. He was in a tree, and it was part of the tree. When he left, it merged with the tree and sprang out at him. It was wrapped around him when he killed it. I had stuck with the idea that it merged with things, so it's death caused part of it to merge with his Leather Armor and gave him Serpentscale Armor. He loved that.
Make up your own stuff and just remember that you can do just about anything. Roleplay a lot so that they don't just think that the game is about combat. The system is combat focused, but roleplaying doesn't require rules.