These mods are MASSIVE texture packs that hold many refurbished, redone, and even reimagined textures. Here we have listed the best overhauls to start off with. You can customize and switch between textures to find the best looking one's that fit your taste. Don't forget that these are just general texture packs. If you want the BEST results don't use the official 2k textures by Bethesda.
aMidianBorn - Book of Silence
Texture overhaul mod, best known for it's weapon and armor textures.
Also covers creatures, unique items and dragonborn dlc.
This is both a fix and a texture pack. The fix is to the vanilla weapon and armor meshes, enabling environment mapping and correcting bogus environment mapping values. The texture pack component is designed to take maximum advantage of environment mapping to produce realistic looking metal weapons and armor.
There's an expansion for Unique Uniques and Lore Weapon Expansion. Got to the weapons page for it.
And here are some notable texture authors that either make random textures with no rhyme or reason and are not all in one pack or download link. It's recommended you download all of their works but it's not necessary.
Known for the RUSTIC series. Has a lot of textures ranging from random objects to clothes and robes.
Guy does wonders with his stuff. You'll see a lot of his mods listed below but he also does custom stuff.
These are non-specific collections of mods that you can use to customize your game. You can interchange these textures to make the game the way you want it to. Now for even better looking textures, you gonna have to get some specific overhauls that work on one or two aspects of the game itself.