Skyrim has so many different Mods for itself, one can get completely lost and confused as to which ones should be installed, and which ones abandoned and forgotten. While I might not be the most hard-core user of Skyrim Mods there has been an extensive list of them that I did use and that I would like to recommend.
The Mods come in different categories, those that you should consider essential and those that are optional (or enhance a specific type of gameplay). This list is still a work in progress. If you have suggestions of your own please post them in the comments!

Frostfall in action. This camp is something a player set up. A Large Fur Tent, campfire, cooking pot and a leather rack.
Before You Download Mods…
Having a whole lot of Mods can lead to confusion, especially when installing or uninstalling them. I personally used Nexus Mod Manager to keep a grip on all of them. Nexus Mod Manager can be used for a variety of different Video Games, not just Skyrim, and it’s very easy and intuitive to use. Since most Skyrim Mods can be found on the Skyrim Nexus you can use the Manager to quickly begin downloading new Mods, and installing them. Some Mods recommend using LOOT, which I also used when managing my plugins, even though the Nexus Mod Manager offers a similar option. For installations however I did use the Nexus.
You can download the Mod Manager here.
The Essential Patches and Mods
While most people might say that the essential Mods for Skyrim are those that improve its textures, audio or visual effects I would say that before you download anything else download and install the Unofficial Skyrim Patches. Depending on which DLCs you have download and install these Patches in the correct order.
The Unofficial Skyrim Patches fix a lot of tid-bits, bugs and introduce a few small changes that greatly improve your experience. A lot of other Mods also can work together with the Unofficial Patches, so it would be best if you installed these Patches first before you download ANYTHING else.
Skyrim UI (SkyUI) offers you an easier to use UI, which is also very useful when for future Mod support. Some Mods absolutely NEED SkyUI. The newest version of SkyUI also allows for a clearer and easier to use crafting menu, that I personally found to be priceless.
SKSE is also crucial for many different Mods. It’s an essential Mod. It is an alternate launcher for Skyrim, so you will install it into your Skyrim folder and run it instead of the default Skyrim.exe.
FNIS might not be an essential Mod, but some other Mods need FNIS. FNIS in essence allows new animations to be added to the game. So if you plan on using some fancy kill-move or combat mod, or perhaps want to add some new creatures, chances are you need FNIS.
XPMS This is an optional Mod that also often comes up, especially when you want to install new animations. It’s a skeleton enhancement (do not ask me what that is, I just know it’s needed)
Fuz ro D-oh is another small mod that is necessary for some Mods that do not have their own Audio. It’s not absolutely necessary but useful at times.
Content Mods
There are many different Patches introducing new weapons, armor, creatures, etc. I personally really enjoy using the following:
Immersive Armors – Lots of additional suits of armor, helmets, cloaks, etc. Already at the start of the game you can see guards, bandits and other NPCs using them. This Mod also gives you a LOT more smithing options, though you still need the right perks to make them.
Immersive Weapons – Similar to Immersive Armors, you will gain access to a lot new weapons. All of the new Weapons and Armor from these two Mods can be smelted down. So if the shopkeeper does not want to buy fifty Steel Warhooks you can smelt them down for ingots, and make yourself some fancy armor, or weapons.
Cloaks of Skyrim – A Mod adding a lot of different Cloaks to the game. These will include cloaks that guards use, representing their cities. It’s a fancy addition, even if the cloaks do not have much mechanical use.
Winter is Coming – Similar to Cloaks of Skyrim, Winter is Coming adds cloaks, but these are akin to large fur-pelts, rather than cloth or linen cloaks. They do not only look nice but work well with Frostfall.
Read more: Skyrim Mods You Should Try