I want to know how people are deciding this, especially since "best" is such an undefined term. Is it who can perform a predetermined feat to the highest degree (eg. reading minds: who can read the most at once), who can perform the most complex feat (though how complexity is defined is then a question), who can perform the most different kinds of telepathic feats, or some other measure? I personally think the first option is a pretty solid way to compare, but it skips over the ability to use telepathy in various ways, which I don't think should be overlooked.
Thanos should be on this list.
Most of the people her are batter Telepath's than him
Yes but the list is 12 long, naturally some will be better than others. In my view he should at least be on the list. I don't know everyone inside and out to make a judgement call of who is best, especially since no standard has been mentioned.
It should be J'onzz and Despero IMO.To J'onzz,telepathy is the closest word to describe how Martians normally communicate and J'onzz is the best.J'onzz has unknowingly kept the souls of his dead race in his mind and taken on those with great TP resistance(like Green Lanterns)and planetary telepaths(like Mageddon).J'onzz has shown to be a ridiculous telepath and among the best of both worlds. The reason J'onzz can beat others in a TP battle is not just his out of this world(get it?)TP,but the fact he thinks at a faster rate that's on Superman's level so he can enter your mind before you put a defense up.Now Despero I would put higher.Why?Because Despero defeated J'onzz in a TP battle with little trouble. Despero has shown to be his TP superior in all their encounters.Despero is like J'onzz:a TPing monsterous Team buster but on a higher level :)
This is between Xavier, Martian Manhunter, Cable and Despero.
Despero has everybody here in illusion and mind tricks by far. Xavier has better feats than everybody here in bypassing psychic barriers and defenses and mental subjugation. Martian Manhunter is superior to everybody in size and ranged feats and Cable has the raw mental projection and solidification of psychic powers. He also has by far the best mental barriers feats in here along with Apocalypse.
Personally, i would take Cable as the best mental user between them, he's not restricted to only a few ways to exploit his powers and has actually done more versatile feats than the others. say illusions, mental blocks, high degree of telekinesis, high degree of mind reading, mind controlling and has even blocked the abilities of other high end users. However, he lacks the potency the other have in determined fields. He's also handicapped because of the cybernetic virus which needs more than half his potential to keep his body together.
Anyway, these particular feats are few of the best i've seen, and for that reason i would pick him.
His fight with Nate Grey was about to alter the very fabric of reality, in other words, reality warping. Even though it didn't happen, the Astral Plane was affected, reaching the telepaths around the globe when Nate Grey unleashed a bit of his power abruptly...
What makes this feat impressive is the fact people like Xavier was suffering greatly because of this while Cable was fine and dandy while keeping his virus from taking over... and lastly, he managed to do what no power on earth would have been able to do... He restored Nate Grey's powers by reaching the deepest places of his mind.
In other words, he restored the powers of possibly the most powerful telepath in that moment, although he almost died in the instance.
Cable may not be the most powerful in specific fields, but he's most probable the most versatile as well as the one with most potential in this group. I could change my mind though.