Akali

pantheon. hands down.

Jax, fiora, possibly the new urgod?

All the other options are for top except Fiora maybe, and I see Akali mid more than top/jg. So, personally I've had a lot of success with Lux. As long as you can keep your distance and play safe, she can't touch you, and you can easily burn her down. Combine that with Akali being fairly squishy, if you do land a full QER combo on her, if she lives she'll be hurting and will need to back, giving you plenty of time to farm even if you don't get the kill.

- Both have weak early games but Diana's W can negate pretty much all of Akali's early damage. Diana's E can pull Akali out of her Twilight shroud too. After level 6, Diana has quicker burst. There's a good chance Akali will buy an early Banshees Veil - or at least some of the components - which delays her from buying Hextech Gunblade

- Akali needs to be on top of a champion for a decent period of time - which allows for Ekko to set up his W and possibly burst her with his R.

- Karma mid (albiet a bit weak) can poke Akali for days and if Akali jumps on her, Karma can root her and reveals her in her Twilight shroud.

- He can poke you hard too and his R ruins Akali's engage.

- His passive is strong against Akali and his Q poke is unavoidable. Engaging on him will usually result in him stunning you and out-trading you.

- Her spammable early shield makes it hard to trade against her - and like with Pantheon - engaging on her will likely result in you getting stunned and her out-trading you.

- Since he's ranged - he can harass her hard. And his Q blind hurts her engage.

Swain hard counters her you just outheal her damage