Haggar

going off of what we've seen so far I've got a list of Haggar's powers.   Consider this entirely subject to change as the show progresses and reveals more details (trying to keep this spoiler free beyond season 1 so you should be safe)

• sense.  Haggar is show to be able to sense auras in the first episode and across a huge distance too.  I am going to head canon that the corrupted quintesence crystals she was surrounded by were needed to boost her ability to that strength but Haggar has the ability to sense and recognize specific auras to the point that she recognized Altean energy when the pods first released Allura and Coran.  I'm going to say she can't use it like a tracking device, just a general awareness and I'm going to say that she can tap into that insight at will but that without the crystals and the preparation needed its very reduced.   Perhaps to the size of a star ship, certainly not to anything as large as a whole planet or fleet and again, even at short range, it can't be used as a tracking device and she actively has to be searching for either something she's familiar with the feeling of or else something that she specifically isn't.  It does make her very hard to sneak up on and I will headcanon that that's how she was already lying in wait for Shiro in the last episode of season 1, fully aware the second his aura came onboard and guessing easily enough the route he would take.
• life drain.  Haggar and the other druids are shown to be able to drain the very life essence out of any living thing and bottle it in a useable form called quintesence.  There seems to be some ritual involved in doing this so in large quantities I'm going to say that the process requires preparation time and certain props to pull off large scale.  I am however going to head canon her a life force vampire and say that she can 'sip' the quintesence out of beings without needing prep time and, possibly, if uninterrupted for long enough, can drain them dry.  I like the theory that her entire race have always been psi-vampires but on such a low level that, while they were the nightmare lurking in the closet of many races, they were containable and not threatening en mass.  Until someone came along to unite them and push their ability to evolve via science and magic to the point where it could be used as a galaxy wide weapon. (maaan, I LIKED that headcanon)
• power balls?  Haggar can create black spheres about the size of a baseball at will from her palms.  These seem to be a form of pure dark energy and are used both offensively and defensively as she can launch them but also use them to block blows with enough strength to knock her attacker backward with the force of the rebound of energy.  Just for the moment I'm also going to include the energy beams she can apparently shoot from her hands as well in this point.  With the right props in place, she can also apparently launch a much more vast and devastating attack like the one that disrupted the wormhole the Voltron team was escaping through in the final episode.
• duplicates.  Haggar can create multiple illusions of herself that seem to most to be completely solid and real.  They're substanceless, so she can't attack with them but they do serve as an excellent distraction if she floods an area with them and uses them as cover for her own attack approach.  So far only Allura has been able to see through them, whether because of her specialized life force energy or the fact she's Altean.
• fugly claw attack (let's include the fact that her claw attacks seem to leave lasting damage that continues to get worse the longer its allowed to go on and apparently requires a healing pod to cure.  Plus they've got a cool glow!)
• instantaneous teleporting
• shape shifting (and since she lifted Shiro up by his throat, gonna add super strong to the list too)
• also fucked around with either his perceptions or the environment by coating Shiro in black goo and then taking away all the light (leaning more toward her fucking with his perceptions than actually being able to alter the surroundings)
• minor gravity control? (or mild telekinesis?  idk, she lifted Allura up in the air and dropped her from a distance)
• where IS her cat?  That thing kicked Shiro's ass in the first series
• mad science/magic skills for new fangled arms and monster creating
• fucking with people's heads (she really LOVES this one)
• lying.  Haggar is very, very good lying.  She will lie to you.  And she will lie to you well.  Because there's no lie as easy to swallow as one that's just a twisted truth.  Don't remember how you got your arm?  She'll tell you.  It just might not be the truth.  Or it might be.  Because the only thing better than a believable lie is an ugly truth.  She loves them both and good luck figuring out which one she's giving you.