In my world, everyone has some sort of power ranging from enhanced physical abilities to the ability to manipulate fire and energy. I'm having balancing issues with telekinetics vs strength/speed enhance. While the enhancers are fairly tough and can generally tank and defeat a fire or energy manipulator, I can't figure out a way for one to stop a telekinetic from simply picking them up and attacking while they are effectively helpless. Telekinesis is simply the ability to make things move NOT a form of energy manipulation. Limits are: Requires more power to affect part of a body as opposed to a whole. Most combat class telekinetics can lift a maximum of 600lbs (about 272 kgs). When manipulating multiple objects most TKs can only lift a combined total of 50 to 60% of their maximum weight. Telekinesis is not limited by volume
You can balance things out by Making the TK's (telekinetic) a finesse class. Being able to move objects, even if it's only lightweight objects, could be extremely powerful. Having them able to lift more than 200 kgs makes them insanely powerful. In the interest of making things fair for the others, I'd limit them to lifting a max of 100kgs, and make them subject to fatigue very quickly. That way if they pick up Mr. Tank, they can't hold him for very long, and won't have the strength to effectively pummel him at the same time. Even So, with skill, they are still very dangerous.
So how can the more run of the mill hold their own? Ambush. A TK can't finesse things if they can't see it coming. Everyone needs time to react. Speedsters should be OK if they can blindside one. Mr. Tank may be able to outlast one in a one to one slugfest.
A newbie TK would be vulnerable, but a skilled and subtle TK has all kinds of options open to him. Grab an opponents shoe and jerk it forward when he takes a step. Grab their shirt and choke them out. Play with a handful of nails and launch them a super high speed. Hide in the corner and drop a ratcheting strangulation cord around the neck. None of these require great strength, and a TK could mix it up enough to be really unpredictable. That's why you might have to cap their abilities.
Here's my suggestion. You should borrow a page from the web serial Worm (if you haven't read it, check it out, it's awesome) and posit that the more directly offense-based psychic abilities/superpowers or whatever in your setting come with a built-in mental block that prevents a person from using their powers to directly affect a human body (i.e. telekinetics can't pick people up and throw them with their minds, and pyrokinetics/cryokinetics can't boil/freeze the blood inside your body).
Why? Because it prevents them from subconsciously using their powers on their own body. If they have some sort of psychological element at play that prevents their powers from recognizing a human body as a target, then they can't hurt themselves accidentally while using them (or even thinking about using them). It's a cute little idea, and one that I think a lot of people with more harmful superpowers would ought to have just to prevent some seriously messy accidents from happening.
If you have figured out the weight limits you should think of distance. Is the TK able to lift the same weight from 1 meter that from 5 meters away? What about 10 meter? 100? 1 km?
Also think of the equilibrium axis: Does the TK grab the object as a whole or from a specific point? because if they lift from the wrong place the whole thing will tip over.
Telekinesis requires large amounts of concentration. If the telekinetic is lifting something as large as a person into the air, they need to focus so much that they can only use telekinesis on that person, and can't telekinesis anything else or do anything else.
Furthermore, telekinesis abilities decrease greatly with range, so that you can't lift someone up to a lethal drop and then kill them. You also need line of sight to use telekinesis, so you can't just sever an artery or a nerve and instantly kill the target.
Telekinetics still have a lot of options open to them (launch sharp objects, try blunt weapon damage, make others lose their footing, etc.) but now they aren't too overpowered.
The telekinetic moves things via astral projection. He projects his body and then at that site, his body can do whatever his body can do. Choke Vader style - yes. Trip - yes. Surprise wedgie - oh yes. Super high speed nails - no. Lift 100 kg - maybe if he worked out a lot. 600 kg - no. Move a hammer through the air - yes, as fast as he can run carrying the hammer or as fast as he can throw the hammer. If he does the running option he can whack things when the hammer gets there. Throwing he will have to pick it up again.
There should be a range: you cannot affect things you cannot see. If you can Vader choke from the next county that is not fair. But if you could only choke within visual range you are a sniper, and your targets have a chance to stumble out of sight or maybe determine where you are and come kick you.
You could just have your telekinetic massage his temples while at work, Xavier style. Better though is if his body actually has to do what his astral projection is doing. Because I love mimes and there are not enough psychic mimes.
This gives a clear limit to what the TK can do. Still an awesome superpower but now your TK can't kill a herd of ninjas with a flare of the nostrils. A telekinetic who could use a sword could fight you from 20 feet away and would be very hard to beat one on one.