In the Lord of the Rings and Hobbit series, the dark lord Sauron is more or less the central antagonist of the entire saga, even if he isn't exactly front and center the whole time. Sauron is a magical being known as a Maia, and as such, he possesses many powers and abilities that make him a formidable villain. Some of these powers came with him when he entered Arda (the physical plane where Middle Earth and its surrounding landmasses exist).
Whether he is under the command of his master, Morgoth, or attempting to seize power for himself, Sauron has always used his natural gifts to oppress the free people of Middle Earth and beyond.
8 Superhuman Strength
Sauron is neither a Man, Elf, Dwarf, nor Hobbit. He is an Angelic being created to assist the Valar in shaping the very world itself. As such, he is not constrained by the limitations of a biological, mortal form like Men are.
A great example of this can be seen in the first film, during the Siege of Barad-dûr, in which he is able to use his gargantuan mace to bash around multiple opponents at once with just a single swing. The One Ring has an effect on this strength as well, amplifying it to even more terrible proportions.
7 The Power of Deception
In more ways than one, Sauron is a master manipulator of virtually every race in Middle Earth to a varying extent. At full strength, Sauron was able to convince others to do his bidding through various means. He was initially able to trick the Elves into creating the rings of power that were to be gifted to the leaders of each race. Though the Elves saw through the trick in time, the Men weren't so lucky and were converted to servants of evil.
He was even able to corrupt many the Numenorean people to the point that the once great civilization of gifted Men unraveled itself due to the jealousy and greed; qualities sown into its very culture by Sauron himself.
6 Ability to Shape-Shift
When Sauron attempted to deceive the elves, he disguised himself as a benevolent entity called Annatar the Lord of Gifts. He used this fair form to set in motion the creation and distribution of the rings of power that he planned to control using the One Ring.
This is just one of many forms that Sauron has taken over the millennia. He has also taken the form of a necromancer in The Hobbit films when hiding out in Dol Guldur, and of course would later take on his infamous "Eye of Sauron" form during the War of the Ring.
5 Enhanced Durability
As an angelic spirit, Sauron is resistant to most forms of conventional weaponry when at full strength. This is true for both his physical form and as the Eye of Sauron, where he cannot really be interacted with at all. It should be noted that, while Sauron is resistant to conventional weapons, he is not immune to them, as he was defeated by Isildur, who was able to cut Sauron's hand with his father's sword.
This weakness associated with his physical form is rectified when Sauron assumes his "Eye of Sauron" form, where only the destruction of the One Ring can truly hurt him.
4 Ethereal Control
Sauron is ironically known more for his non-corporeal form than he is for his physical one. The Eye of Sauron, lidless and wreathed in flame, perched atop Barad-dûr, is one of the most iconic images in modern cinema even, but this is not his "true" form.
After the loss of the One Ring, Sauron's body was destroyed, but his spirit still remained intact. This ability, to control his "soul," so to speak, is what allowed Sauron to survive his initial defeat at the hands of Isildur. While Sauron isn't quite as strong in this form, he still a very grave threat to the people of Middle Earth.
3 World Manipulation
Mount Doom (and really Mordor as a whole) is almost like Sauron's personal little playground. His ability to physically change the world around him is undoubtedly due to his angelic nature, being originally created precisely to assist the Valar in shaping Arda on behalf of Eru Illuvatar.
It's not directly stated in the film, but the land of Mordor, and Mount Doom especially, is constantly influenced by Sauron ever since he chose it be his domain within Middle Earth. The very fires of Mount Doom are under his command, serving as the forge in which he created the One Ring.
2 Master of Dark Magic
There is a reason Sauron is referred to as the Dark Lord. He is not only naturally attuned to magic (he is a Maia after all), but he can wield it with far greater skill and efficiency than any mortal being. Sauron's brand of magic, however, is inherently evil in nature and is thus referred to as "dark magic" or "witchcraft."
This can be seen in his ability to corrupt others to serve his will, as well as his capacity for crafting objects like weapons, armor, and jewelry that are imbued with magical properties, like the One Ring. It can certainly be argued that virtually all of Sauron's abilities stem from his magical nature.
1 Natural Immortality
As a Maia spirit, Sauron can't really die by natural means and will live forever if left undisturbed. In fact, he lived for thousands of years in a physical form just like Gandalf or Saruman before he was defeated by Isildur. This defeat does prove, however, that Sauron can essentially be "killed" from the perspective of a mortal — but only if certain conditions are met. Even then, his spirit never truly dissipates from the world. It merely ceases to be a threat in any real capacity.
Gandalf himself states that Sauron can never again threaten Middle Earth, but stops short of declaring him officially dead.