Top:
: Despite recent nerfs, she's still pretty good, fits well with most teamcomps, great at dueling. Also, if you ult to initiate, you can E away if need be. In terms of cons, she's singletarget, meaning if your behind, or get focused down in teamfights, you don't do much.
: There is no engage, quite like a Kled engage. You've got damage, tank stats, and a dash to run/intiate with. Also, if you can land skillshots, basically no-one will escape you. Cons are, singletarget, and playing from behind is really hard.
Mid:
: If you're looking for a champ, who can get out of bad situations easily, Ekko's your guy. With multiple dashes and slows, he excells and chasing, as well as picking off enemy squishies. Con-wise, he is melee, so you will most likely get bullied, and he is somewhat hard to master, due to his delayed damage.
: This is more of an opinion, but Karma is a pretty good midlaner. You can go straight damage, and just oneshot peeps, or you can build utility or tank. Its up to you. However, unlike every other champion on this list, Karma doesn't have a dash to escape. Despite this, your W + E combo is pretty useful in getting out of bad situations, as it snares the enemy, and speeds you up. For the bad bits, she's apparently totally boring to play, and playing her may lead to you hating Riot, with a passion. Actual cons are, she hard to play against a good jungler, since you aggressively push most of the time. Also, she is excellent at baiting, but, you do have to master shield timing.