Professor X's powers and abilities
Telepathy
As one of the most powerful telepaths in the world, Xavier has a wide array of telepathic powers. An example would be when Charles scans a person's brain and finds any information he needs, including memories. He used this power to help Logan unlock his memories, and in the 70's when he used this ability to search the mind of a woman, so he could see what flight Raven was going to take. Charles' telepathic abilities were so great that Apocalypse desired to possess his body, despite already having extremely powerful telepathic abilities. Thanks to having his powers greatly enhanced by Apocalypse, Charles' telepathy is now at the point where he can communicate with everyone across the whole world without the aid of Cerebro (which was destroyed by Havok under Charles' orders, as Apocalypse was trying to take control of Cerebro).
Telepathic Cloak
He can make himself invisible by manipulating the minds of others. He used this to hide himself, Magneto, and all the assault troops while en route to the dacha of the Russian general without being detected while in the back of the caravan.
Telepathic Communication
He is able to telepathically communicate with others. He demonstrated this when he communicated with a young Cyclops, and when he communicated with Moira and Erik.
Mental Detection
He is able to sense where nearby mutants are. He demonstrated this when he sensed that Rogue had left the mansion and was at the train station. This ability is enhanced when he uses Cerebro. He was also able to find out that Jean Grey had left the X-mansion.
Mind Control
He is able to manipulate the minds of others to get them to do what he wants them to do. He does not like using this ability to make people do what he wants them to do all the time as he said when talking to Magneto while going to Jean Grey's house when she was a child.
Mental Possession
He is able to enter the mind of another to control their body and see from their perspective. He demonstrated this at the dacha of a Russian general and possessed the mind of a guard.
Mental Sedation
He can make others fall asleep simply by telling them to.
Mind Transferral
When his body was destroyed, he transferred his consciousness into a host body, which is seemingly an advanced version of mental possession. Although, this is never explained or made clear. It is believed the body he transferred himself to is his brain dead twin brother Patrick, his powers being enough to resuscitate the body, though the body shared Charles partial paralysis.
Paralyzation
He can mentally paralyze others, making it appear as if time has been stopped, although he could also paralyze only the body without rendering people's minds frozen as well. If Charles transfers much of himself to possess and paralyze the body, he can feel pain and discomfort his target feels as if he was experiencing it himself, though without any harm coming to his real body.
Mental Link
He has the ability to develop a mental link with any person which remains as a connection to that individual. This was shown when Jean Grey linked with him to communicate with the others in the X-Jet before perishing. Charles uses this power to project his mind into the future by linking the future Wolverine's mind and use them as a bridge to it where he is able to connect to and converse with his future self.
Mnemokinesis
He can manipulate the memories individuals. Xavier can erase, restore, or even implant false memories into a person's mind.
Memory Implantation
He once threatened Wolverine, that he could make him believe he was a six-year-old girl.
Mental Amnesia
He has the ability to cause loss of particular memories and amnesia in another person or group of people. Here, he used this power while passionately kissing the beautiful Moira MacTaggert and makes her forget all the time that she spent with Xavier and the mutants (although she recalls fragments, including the kiss). This might have been used to save himself and made it look like Jean killed him.
Memory Restoration
Along with erasing memories, Charles has the ability to restore a person's memories as well. This was demonstrated when he restored the memories of Moira MacTaggert, which he had initially erased, causing her to remember all the time she spent with him.
Telepathic Illusion
Charles is able to generate realistic illusions. Charles could make himself and others invisible to others. Professor X uses this power to convince Mystique to not kill Bolivar Trask. His illusions took the form of himself, but able to stand. Any damages he had on his body would appear on his projection. His illusion based projection allowed him to perceive events from afar with only his projection being present.
Psychic Barriers
Charles was able to put mental blocks in Jean Grey's mind so she couldn't unlock the Phoenix part of her personality.
Psionic Blasts
When his powers were boosted by Cerebro, Charles had enough power to cause every mutant in the world to experience a lethal, excruciating pain. He was also able to make every human experience the same lethal pain when Magneto reversed Cerebro. These blasts could not effect Magneto, as he was wearing his helmet. When his powers were out of control due to mental illness, Charles would release psychic pulses that could effect hundreds of people across over a mile radius. They paralyzed and tortured all those effected, and could have killed anyone who was forced to experience it for more then a few minutes.
Psionic Resistance
According to William Stryker, the mind control serum will have no effect on Xavier, as his resistance to other people's telepathy make it very difficult to control him. He can resist psychic attacks from others and protect his allies. It is likely Emma Frost could not telepathically attack Xavier or Erik as Xavier defended both their minds from her, though he did feel a slight sting from her when trying to read her mind.
Animal Manipulation
Charles was shown to be able to affect animals with his telepathic abilities when he concentrated on a group of stray horses belonging to the Munson family and having them return calmly to their owners. He was able to do this when not taking his medication for his mental illness, though he ran the risk of having a psychic seizure.
Abilities:
Genius-Level Intellect
A natural genius, Xavier is a leading authority on genetics, mutation, and psionics. He also possesses considerable expertise in other life sciences. He is highly talented in devising equipment for utilizing and enhancing psionic powers. Xavier is also quite the masterful tactician and strategist, effectively evaluating situations and devising swift responses.
Skilled Strategist
Skilled Leader
Multilingual
Xavier has shown to be fluent in many languages. He was shown to be able to speak Russian. During his speech to the whole world, he was able to speak several different native languages to respective countries. He was able to speak Spanish to Laura. However, this could be a result of his psychic abilities and he translates his voice inside people's heads so people who speak different languages could understand him.