First are the structures. They are all exceptionally rare and include 10 dragon lairs and a daedric lair.

Daedric Lair:

The daedric lair is a dungeon found in the overworld near just about anywhere. They contain valuable loot and have spawners that spawn Dremora.

The dremora are powerful warriors with 75 health and fast agility. They may taunt you by saying things that would demoralize you. They wield daedric swords (powerful swords that cause close up knockback to nearby enemies when hit). They will drop daedric hearts that are used to craft the sword, the bow, and the armor.

Dragon Lairs:
These are areas of small land with things known as shout walls that contain the shouts in this addon. They also contain chests with powerful loot but are guarded by aggressive dragons. Getting too close to a dragon will cause it to fly into the air and become a miniboss with 3 phases. It includes the flying phase: one that shoots a constant onslaught of fire breath, having 600 health. The swooping phase: swooping down to the ground to attack you at an unbelievably fast rate, having 700 health. And the ground phase: where it falls to the ground to shoot at you with fire breath and bite you upon close disturbance, having 800 health. The dragon will upon defeating the third phase and drop dragon bones that are used to craft the armor, sword, and bow.
 

The dragon waiting:

The dragon in the flying phase:

The dragon in the swooping phase:

The dragon in the ground phase:

The dragon's loot:

The powerful items in the chest:

The shout wall:

Items:

The basic items include the shout core and the shout reader.
The shout reader is needed to break the shout wall blocks to obtain the shouts.

The shout core is crafted like this:

And the shout reader is crafted like this:

An important item needed later in the game is the dragon priest mask:

This is needed for the portal to sovngarde. It will be used by placing cobblestone in an end portal shape, and throwing the mask into the center. The portal will transform with unknown blocks.

Upon openening the portal, a dragon priest named krosis will spawn above it. He has 1000 health, shoots regular fireballs towards you, summons frost atronaches to attack you, and has a meteor shower attack.

Defeating him will make him drop a daedric sword, 10 shout cores, and a dragon bone chestplate.

Apart from that, the portal to sovngarde holds the world eater known as Aslduin. Entering, you will see a strange looking dragon. Getting closer will cause him to become hostile. He has 2000 health, a bite attack, a meteor shower attack, fire breath that causes lightning, and he will attempt to knock you off of sovngarde.
 Sovngarde is quite small at the moment.

Shouts are next up on the table. They are obtained with the shout reader and shout walls. There are 10 in total. Whirlwind sprint, summon durnehviir, unrelenting force, clear skies, storm call, fire breath, frost breath, elemental fury, dragonrend, and marked for death. They all have their own abilities: summon durnehviir will summon a dragon that fights monsters for you. Whirlwind sprint will shoot you forward as a boost. Unrelenting force summons a powerful shout that knocks your enemies away an extraordinary distance. Clear skies will clear all skies from any weather. Storm call will call upon a thunderstorm. Frost breath will leave an ice path, freeze enemies, and cause a frostbite to enemies. Fire breath will burn enemies, leave a fire trail, and cause a wither effect to nearby enemies. Elemental fury will leave you with a speed and agility boost causing strength to increase. Dragonrend can be used against any flying dragons to force them to land into their ground phase. And Marked For Death will cause enemies to have extreme debuffs to a point where they are extremely easy to kill. NOTE: players aren't affected by many powers of the shouts.

Bows are simply items that will fire arrows according to their type. They are crafted like normal bows, but the daedric bow is crafted with daedric hearts and the dragon bone bow is crafted with dragon bones.

Next are the armors and the swords. The daedric sword has a unique feature that will knock away opponents once they are hit by the sword. The dragon bone sword has nothing special but does more damage. The daedric armor is a strong armor crafted with daedric hearts while the dragon bone is even stronger but longer to craft with dragon bones.
 

V2:
This had to be updated for 1.18, but there a few changes and additions.

For starters, dragon animations were improved and the dragon bone sword has a unique fire property. The biggest addition is magic scrolls, and there are 3 mysterious ones you can make with the magic scroll which can be crafted like this:

Loot has been improved and the dragons were nerfed.

End:

This addon will be updated overtime. 

I have a channel on youtube:  https://www.youtube.com/channel/UCZOrxBoGBJtiFdeBFSLQ6CQ

I also have a discord server:  https://discord.gg/ZMvvQBbMdd