Augment

Augment, in the general sense, is the designation given to a person or group that has been biologically altered to be physically and/or mentally superior to their base species. In more specific usage, the term "Augments" is applied to the genetically-enhanced "supermen" of Earth's Eugenics Wars, and to similarly-altered humans in the centuries after.

The Eugenics Wars
An early occurrence of augmentation was the product of Chrysalis Project on 20th century Earth which aimed to create a race of superhumans. Unfortunately, as was stated in the journals of one of the scientists of the project shortly before he was murdered, "superior engineering breeds superior ambition." The supermen went mad for power and attempted to take over the world governments and installed themselves as leaders while considering unaltered humans a lower class. These augments were tyrants that devastated the world and united it against them in a conflict that would be known as the Eugenics Wars. The last of the supermen was Khan Noonien Singh, who managed to escape from Earth in a sublight transport. After the Eugenic Wars, Earth banned development in this field of research, though ethical debates lead to keeping hundreds of augment embryos in cold storage. (TOS episode: Space Seed and novels The Eugenics Wars)

Following the war, several hundred genetically engineered children were taken to Alaska to live out their lives in peace. 

Some people and/or Augments did indeed escape Earth during and after the Wars, often ending up supporting Eugenics anyway. 

The Neyel
When the humans of the O'Neil asteroid colony were stranded far from Earth, they decided to defy Earth laws on genetic modification and began to augment themselves. This eventually led to altering themselves into a vastly different species who called themselves the Neyel. (TLE novel: The Sundered)

The Augment Crisis
In the 22nd century a scientist, Dr Arik Soong, working Cold Station 12 where the 20th century augment embryos were stored, saw potential in augmentation and decided to continue the development of the program and managed to escape with several of the embryos. He raised them as his children until he was captured by Starfleet. A decade later, these children sparked the Augment Crisis that nearly incited a full-scale war between the Klingon Empire and the relatively new interstellar power of United Earth. The Augments once again attempted to make a break for power and showed that they had no trouble with committing genocide on other worlds to achieve their goals. (ENT episodes: Borderland & Cold Station 12)

The group eventually turned on their "father," who was attempting to modify their genes to remove their aggressive characteristics. They and the remainder of the 20th century embryos were killed when the starship Enterprise destroyed their captured Bird-of-prey. (ENT episode: The Augments)

Klingons
The Klingons were both impressed and fearful of the potential of the Human augments, and were the next to experiment with augmentation. Using gene therapy based on Augment DNA they obtained from the wreckage of the Bird-of-Prey the Human Augments had commandeered, they attempted to create their own augments. Their experiments were initially successful in increasing strength and intelligence, but did have two side effects: the Klingon cranial ridges dissolved, and eventually led to an agonizing death as the subject's neural pathways degraded. One of the test subjects had Levodian flu, and the virus combined with the Augment DNA to create an airborne plague that quickly spread throughout the empire, infecting billions of Klingons and causing them to lose their ridges.

All of the infected Klingons would have eventually died, but fortunately for them, a cure was developed by the Klingon Antaak and Dr Phlox of the Earth starship Enterprise. Whilst the cure prevented the deaths of many Klingons, it did leave them ridgeless, an effect which would be passed onto their children. These Klingons became known as QuchHa'. 

The Second Attempt
Dozens of years later, a Klingon scientist known as Qadar attempted to create "enhanced" Klingon warriors called M'tachtar, which he re-engineered (along with himself) into a force that would be used against the Federation. He was stopped and exiled along with his warriors by his Rustaai-cousin Emperor of the Klingon Empire Grannoch. They remained on an uninhabited planet until they managed to take over the USS Enterprise (NCC-1701) under the command of Captain James T. Kirk. Qadar and his followers attempted to return to Qo'nos and take command of the Empire, but were quickly defeated. They still returned to Qo'nos, but their is fate is unknown. Presumably, they were executed for their attempted coup against the ruler of the Klingon Empire. (TOS novel: My Brother's Keeper: )

24th Century Augmentation
Earth's restrictions on genetic modification eventually spread to the Federation, however there were a few colonies that performed the necessary operations illegally. This included operations that did not bestow the full "gifts" of augmentation, but rather specific aspects such as increased intelligence or improved motor skills. Ethan Locken and Dr Julian Bashir were two such augments. (DS9 episode: Doctor Bashir, I Presume? and novel: Abyss)

There was also a group of humans on the planet Hera who ignored the Federation law and routinely practiced genetic modification to a similar degree of the augmentation in the Eugenics Wars. This group called themselves Herans and believed that they were superior to "Old Humans." They planned to use a genetically engineered virus that would have converted all newborn children into augments, however, they faced a human renegade faction on their homeworld who resisted their attempts. (TNG novel: Infiltrator)

List of known genetically engineered individuals

 * Khan Noonien Singh
 * Stavos Keniclius
 * Vasily Hunyadi
 * Julian Bashir
 * Sarina Douglas
 * Dr. Phoolan Dasall
 * Jack
 * Jaya
 * Joachim
 * Joaquin
 * Kali
 * Lauren
 * Ling
 * Malik
 * Mara
 * Marab
 * McPherson
 * Otto
 * Patrick
 * Persis
 * Raakin
 * Rodriguez
 * Saul
 * Udar
 * Yavar