Magic resist items are NOT designed to be anti-ADC like armor items are.
Don't get me wrong, 
is absolutely godlike against it but we don't have any options besides it like we do with 
.
Either make more anti-DPS magic resist items or make them deal physical damage so we can build the armor items you specifically designed to counter them.
(Champs I'm referring to: 
kinda this guy too 
)
Gear Jammer1 votesI really want to go bot lane with corki... but im afraid no one remembers him bot lane.... and i would get flamed
Z3Sleeper1 votesI've seen it. He can still be played ADC. He's just taken mid cuz he's pretty damn oppressive in the mid lane and he doesn't hyperscale like bot lane ADCs.
He's just as obnoxious in the bot lane as he is mid lane, especially with a poke support like Brand to double up on the obnoxiousness.
saltran1 votesHe's not played bot because he has a lot of power in the package that isn't really useful as botlaner, and since he has it he has lost a lot of power in other parts of his kit to compensate and not be busted as midlaner.
VoraciousX1 votesI really don't want Katarina to get MORE problems against "DPS mages" because her passive is all her damage....
Z3Sleeper1 votesAll the more reason to make ADCs deal physical damage.
VoraciousX1 votesAll the more reason to make ADCs deal physical damage.
But you're asking for more MR items to target DPS mages. Adaptive Helm was meant for the likes of Cassiopeia etc, but it fell on Kat too because her passive is all her damage. They don't need MORE vs that, Adaptive Helm is already toxic enough vs her. I do agree with your sentiment that the magic damage ADC niche is pretty much already filled though and Kai'Sa shouldn't have had it as well. She's a cool champion but her late game is absurd. Ninja tabi fills this niche vs auto attack focused champs though.
Z3Sleeper1 votesmake them deal physical damage so we can build the armor items you specifically designed to counter them.
VoraciousX1 votesninja tabi works on all auto damage. No matter the type of damage. Also Kogmaw mostly deals physical damage(bork, guinsoo's, etc), and I'd imagine the others do as well. Problem is they still deal mixed damage. Their passives aren't going to deal as much damage as they do physical though because they're not building AP(unless they are building AP, or they're maybe corki).
Z3Sleeper1 votesThey do mixed but much more magic than physical.
Kog has W, literally every other ability, Wits End, Rageblade, Nashors.
Varus has both W passives, RB, Nashors and builds full AP after.
KaiSa is literally all her passive, which deals a ton of magic damage. Some physical from Q, base AD and RB’s physical side.
VoraciousX1 votesThey do mixed but much more magic than physical.
Kog has W, literally every other ability, Wits End, Rageblade, Nashors.
Varus has both W passives, RB, Nashors and builds full AP after.
KaiSa is literally all her passive, which deals a ton of magic damage. Some physical from Q, base AD and RB’s physical side.
Thing is these champions don't build nashor's that often. They usually go bork guinsoo's wit's end runaan's. For an example, Varus builds Nashor's in 0.68% of games, it isn't even on Kog'maw's most build items list. The only one who occasionally builds nashor's often is Kai'Sa, and that's because she actually has as many AP scalings as AD ones. Wit's End sure, but they build more physical items than AP ones, and you'll see on the damage charts that they always do more physical damage than magic. Not to say it's not a problem to deal with the magic damage portion, as that makes them harder to itemize against, but they always do more physical than magical.
Z3Sleeper1 voteshttp://www.probuilds.net/champions/details/Varus
Kog doesn’t go nash ur right but he goes wits end for a reason and wits even deals magic damage too.
VoraciousX1 voteshttp://www.probuilds.net/champions/details/Varus
Kog doesn’t go nash ur right but he goes wits end for a reason and wits even deals magic damage too.
It does, but these champions build bork as well, which does physical. They also build more AD than AP. Wit's deals magic damage but if you look at your death recap, you're very likely to see a significant amount more physical than magical on on-hit champions, unless they build like Kayle.
Z3Sleeper1 votesNo look again. Varus is literally going AP after Nashors.
Kog is building to maximize his E damage (magic % health) with wits end (magic) guinsoo (mixed but doubles up wits and his E) and ofcourse bork.
Kaisa is building deaths dance, Nashors, Rageblade and then flexes from there. But with this build she is dealing SIGNIFICANTLY more magic damage.
VoraciousX1 votesNo look again. Varus is literally going AP after Nashors.
Kog is building to maximize his E damage (magic % health) with wits end (magic) guinsoo (mixed but doubles up wits and his E) and ofcourse bork.
Kaisa is building deaths dance, Nashors, Rageblade and then flexes from there. But with this build she is dealing SIGNIFICANTLY more magic damage.
Varus is only building Nashor's in 20% of games. It's not core. Looking at JUST YOUR website, Kai'Sa doesn't build Nashor's at all, and Kog'Maw builds it in 12% of games. Yeah, all these champions DO magic damage(and Wit's End is built to play off of that), but if you are killed by these champions, I can almost guarantee your death recap will show you taking more PHYSICAL damage than magic, UNLESS they build AP, in which case yeah they will deal magic damage. But again, these builds you're talking about are ANYTHING BUT CORE, and that's me looking at YOUR website, not op.gg , which Riot claims is the closest to their numbers iirc.
Z3Sleeper1 votesAight I'm not gonna push that any further don't feel like it.
However, consider the fact that these builds are completely viable at the highest levels of play and do deal far more magic than physical damage, regardless of how often they are built.
Dead flag blues1 votes"ADC" means "Attack Damage Carry". No reason they should deal magic damage. It's ridiculous that some ADCs do mages job in a better way than mages.
Critmaster Garen1 votesi think generally adc items are still too strong (mostly crit). and the fact that they get stattic shiv as a burst tool on a champions who is supposed to deal sustained damage is ridiculous.
but is the magic resist version of against ap carries.
you generally want to pick the item against any form of sustained magic damage. be it
etc.
help a lot against and w and 
empowered auto attacks aswell, despite the items armor. the % damage reduction still applies to his magic damage dealing basic attacks and on-hit effects.
i know adc magic damage can get dumb despite these items. i just want to show a couple ways that help you fighting them.
Z3Sleeper1 votesYeah Adaptive Helm is a great item don't get me wrong, the problem is that there is only 1 Adaptive Helm if you get what I mean.
At the same time I don't exactly want more "Adaptive Helms" cuz it'd hurt other mages more than it'd hurt these magic damage ADCs.