There are many Pleiadian civilizations. Some of them are involved with the earth closely. Most connected to us are Pleiadians from the Erran culture. Not all of them live on the planet, but Erra is their home planet. It is the 3rd planet of Taygeta, a star of the Pleiades constellation. Taygeta is visible to the naked eye as a tiny dot. Pleiadians have origins in human culture of Orion. They are related to Arians of Earth as brothers having common parents, the humans from Orion. Currently the majority of humans from Orion have negative relations towards Earth and are largely kept away from earth, as much as possible. Most Erran Pleiadians have good intentions and are helping.
Keep in mind that all aliens discussed are from a different plane of existence, 4th density, and appear on earth only temporarily using dimensional technologies. The aliens don't fly from star to star in their ships. They have technologies to jump from place to place. Their ships just disappear in one place and appear in another.
The ways our galactic friends influence the Earth are limited due to quarantine.
They are channeling their messages to us via psychics and channelers to negotiate the plans for Open Contact with human leaders, to guard the Earth from invaders, prevent the use of weapons of mass destruction, to minimize natural disasters, expand the contact with individual humans, study earth culture, and continue the voluntary hybridization program. Many aliens these days come to Earth as visitors in disguise to walk on the streets and gain an initial understanding of us.
Plans are proposed to the Earth leaders for the open official contact. These plans have been discused for the last 60 years and recently more progress has been made. Normally, a planet at this stage would be already aware of the 4th density neighbors, but humanity as a whole is against the awakening. Its collective will is respected. The main argument for the delay is that open contact would cause the disturbance of minds and the market would crush causing an economic breakdown, which is a real concern. Therefore it is likely that first contact might happen after the economy breakdown, and will assist in recovery with new, more progressive ways.
The Pleiadians of Erran culture are from another layer of reality and usually come to us in dreams and meditations. As such they can choose the appearance.
In their 4rth density they look as tall humans. They are most related to our modern Scandinavians. They are somewhat taller and slimmer than humans. Due to their ecological inclinations they modify their skin to be green or blue and synthesise energy from light. They look very much like elfs from The Hobbit, except their skin and hair color varies. They have very diverse fashions and color their skin and hair. Their typical clothes are loose, one piece togas. When they come to humans in dreams, they adjust their appearance to look more familiar. When they come to our streets physically, they disguise themselves so well, that there is no easy way to tell them apart.
Erran culture is well aware of the Earth's culture and follows our fashions and artistic developments with interest. Historically there are humans from Earth on Erra. They were taken as slaves from Earth in ancient times and since then gained their equality then integrated into society. The whole Erran civilization is telepathic, including the humans. This illustrates that humans are genetically capable of telepathy and it is only the environment that is needed for its development.
Pleiadians developed medicine and have a knowledge of the human body. Their medicine is both spiritual and technological; their medicine involves genetic manipulation and medications. They use dimensional and time manipulations as well.
Although Pleiadians at large are not our direct ancestors, they have common origins with us and they mixed their genes into ours during history.
This happened two ways: naturally and artificially. Some Pleiadians visited the earth and mated with humans naturally. Some of them even settled on Earth. The technological way used artificial gene manipulation to bring their genes to Earth. Pleiadian traits from recent infusions can be seen in the descendants: the descendants are tall, have lighter hair, psychic abilities and are driven to sciences and spirituality. Usually people from each star race keep an eye on their starseeds, come to them in dreams, offer them guidance, channel through them and protect them from negative aliens.