The meta seems to be quite unstable right now. Most top lane champions work and are strong under their own particular niche. There are a couple of outliers, but most of them won't last long being this strong.
Irelia got a nice boost from the changes to Trinity Force, so she's top tier if not the single best top laner right now.
On top of her I'd add Vladimir and Swain (especially swain), both drain mages that are really strong since the mage roster changes. They are certainly top tier in the mid lane, so even in top they may be strong.
Lastly, the annoying "assassins building tanky" ( Fizz/ Ekko) are still strong, but they're not in their previous broken beyond repair state, and they'll get more nerfs soon.
Actually on this newest patch 6.14, Kennen is rather strong in the top lane with the Protobelt. He has great engage with his E and then protobelt onto the enemy team, and ult to get your passive off and stun all of them while doing great amounts of damage. Vladimir is still super strong and Irelia is still a great champ with the changes to Trinity Force.
Another way you could find what champions are in the meta is be visiting this website. Here you can see champion statistics and champions in the current meta. What you should do is go to "Sort Role" and select "Top". Then I would look at the "Play Percent" to determin the best champs.
On top of her I'd add
Lastly, the annoying "assassins building tanky" (
Hope this helped :)