I'd say you're looking for Quinn or Graves.
If you're new (or even below like, platinum) then both are perfectly serviceable. The general opinion is that Quinn is a little bit underpowered as an ADC, but she can be played very well toplane in a manner similar to a more flexible teemo.
Here's how they both work:
Graves is THE instant-burst ADC. He's got a shotgun-blast ability sorta similar to an Ashe Volley, but narrower and higher damage. If he hits people with multiple of the three blasts (i.e. he shoots it from right in their face) it deals even more damage. he's got a dash which also gives him a MS steroid, as well as a "sort-of-blind" smoke grenade. Basically, if you've ever experienced Nocturnes "DAAAARKNESSSSSS" effect, it's that, for anyone who's inside the smoke. If an enemy is inside the smoke they can't see what's going on outside the smoke. His ult is simple and straight forward, a huge AOE execute.
His general playstyle in lane is a massive bursting lane bully. He loves to jump into melee range with the enemy carry, blow them away, smoke bomb them and walk out before they can shoot back. He relies on a surprising level of burst to get kills early, and functions similar to Draven in terms of lane dynamic. you rely on people not realizing you can knock them down from 50-60% hp.
Now, Quinn is a bit more of an oddball in terms of her kit. Her main gameplay revolves around her passive, where her little scout bird will pick out a target, and your next attack will deal extra damage (basically like the difference between a draven spinning axe and regular auto). It prefers the last target she attacked, so what you do is time it to when you know it will come up soon, deal a regular attack poke against the adc, get a second passive attack, use your gapcloser (which resets the passive on the target) and passive attack again for huge damage.
She brings a lot of weird stuff to a team, which is why people dont tend to use her. It's kind of like trying to make use of every little thing in a kit like Elise's where there's a ton of different stuff for you to do and you're not sure what's right and what combination to use. She's got a small automatic steroid+MS steroid for popping her passive, a weird little vision spell that makes it almost impossible to bush juke her, an AOE blind, the strangest little gapcloser+slow+burst thingy in the game, and then you hit R and she's just a bird.
And you go "what the fuck?" because yes, quinn is a ranged ADC that turns into Master Yi when she ults. She becomes melee, gains huge movespeed, her spells become melee range, and she gains a big steroid. The problem? Using that in a teamfight at the wrong time is a great way to get your feathery ass deleted. Her ult has a million uses none of which are obvious. She becomes the only ADC that can split push like a Tryndamere or Yi. She becomes the only ADC that can duel an assassin or bruiser with ease when they get the drop on her. She becomes a powerful roamer who can show up mid and burst down the enemy assassin before they come get her. Quinn is a weird, WEIRD ADC. But the people who like her, LOVE HER. So, if it seems like your style, I encourage you to check her out.
