In terms of pure telepathy, I don't think anyone is much ahead of her. Jean had high end telekinesis as well, so was overall more powerful, but Moondragon has telepathy feats very much on the very top end of the psi record.
She has simultaneously mind controlled an entire planet, for example. When Drax the Destroyer (her father) resisted her psi and was going to battle her, she killed him, using her telepathy to render him brain dead...and yes, he was herald level at that time.
Bottom line, with no psi defense, she could well be a team level threat.
she's had showings that aren't as good, but she's definitely among the best psi's in the MU, and has shown the ability to sense and read minds easily, she's beaten Captain America and Mantis in hand to hand combat, and she can control her body to the point that Daredevil couldn't even detect her heartbeat. She's pierced Galactus' mental shields as well.
She was also genius enough to create machinery to give people super powers, as she did with Angar the Screamer and others, and using her pressure points and such was able to restore Daredevil's sight for a while.