Telepathy is when you own both parts of an elite line pairing, ala Gretzky-Kurri, thus locking out all other GMs on what they produce. Telepathy is the short form of 'Legion of Doom' where you have all three parts of an elite line, or 'team dominance' when you own most or all the significant producers from a team.
Telepathy is relatively uncommon, and Legion of Doom has achieved just twice by my reckoning - the Shadowmen when they actually went out and aquired the original Legion of Doom in it's entirety, and I won my second cup by trading for the Lemieux-Jagr-Kovalev trio to give me my own version.
So who has the strongest telepathy?
1. The Knights Templar - Bertuzzi and Naslund. Note, they wouldn't qualify for Legion status by aquiring Morrison. Why? Because Morrison (despite playing on a line with the aforementioned pair) isn't an elite player in his own right.
2. Personal Vendetta - Forsberg and Gagne.
3. The Severed Heads - Spezza and Heatley (and if Alfreddson were to end up on the 'Heads, we'd be in 'Legion' territory)
There is also one other GM with a significant pairing, though I think it falls short of telepathy;
The Edge - Fedorov and Sykora.
Note - The Ramapithicines don't have any telepathy, but they do have some team dominance in Dallas with Turco, Hedberg, Morrow and Zubov all filling roles.
Who might be telepathic?
The Highlanders: if they swap St Louis or another portsider for Glenn Murray. A Murray/Thornton pairing could be quite frightening.
The Wolves/Great Whites: If either managed to aquire both parts of the Zetterberg/Datsyuk equation they would qualify. I don't see it happening though.
Note: It is exceedingly tough to create telepathy with players from Colorado because the best players are FPs, and on different teams. Tampa Bay has some creative options, but Lecavalier, St Louis and Richards are all spread around with little likelihood of them being traded because of their obvious intrinsic value.
Did I miss any league telepaths? Are there Legions of Doom in the past I should note?