are generally the enchanters, and if you can master Janna or Nami, you become a royal thorn in the other team's side regularly.
Karma can act as one and so can most shield champs, but imo, Karma struggles to lay up the 60-70% win rates. Mage bots are nice, but they don't generally save their adc, and they usually struggle to contribute to a bot lane because minions are always in the way. on Annie, Lux, Karma, Zyra, you're basically betting on being a 5th semi carry or carry, which sometimes doesn't work, because the other team has someone like
who can just in on you and end you.
Karma's primary strength is combining
with her Ult E as a game winner, but sometimes teams don't play tightly enough to use it, or they needed more damage or are timid turret takes. She can prevent damage, but she has trouble healing the damage up, which is why i generally lean on Nami or Sona as a healer. She's also only temporarily a fast mover, and has no non localised hard CC, which means she's a primary target for being killed by
which is a pretty common pick.
is my personal favorite. If you know her bubble mechanics perfectly, her passive perfectly, and go AP instead of active item, she's a monster, both in heals, and in being a fight presence. Land bubbles on 3 champs often = gg team fight. Timing a bubble on a difficult target the very second your R hits them = bye bye hard target if your team knows what you're doing. Knowing that your R also adds up to 300 move speed to your teammates = important to knowing it's not just an offensive skill. Knowing who to E and having the mana to spam it = no one can run from you or your teammates and you're going to get a higher kill participation rate than anyone other champ in the game, which increases your gold take.
I'll give you a hint on Nami's bubble. It takes .78 seconds to fall, so certain champs can abuse that and make it miss.

At least with Yi, at your Elo, there is an opportunity to get him killed every time. If Yi is after you, and you are even remotely tanky, at low elo, Yi will usually Alpha strike you to catch up and begin his engage of you. Alpha strike always lands behind your character. So... the best thing to do is...... Don't throw a bubble as Yi gets close to try to prevent him from reaching you. He's probably in alpha range by the time you do, and he will probably just use it. Throw your bubble as Yi is Alpha striking you. on yourself. Slightly aimed behind you. You will 100% catch yi, which gives you 1.5 seconds to create some distance, which your bubble just procced your passive on yourself, so that's easy. You can apply this trick vs your allies too, if Yi is after them instead. It's not worth ulting Yi, because he won't be slowed.
And ofc, if you're vs a
or
.... save your ult for when their walls are down. keep an eye on them for those opportunities.
I wouldn't ever use Nami vs Akali. Akali you use something like Sona. non target stun. Zyra can trade her 1:1 but it's iffy. Morg's probably better than both.