As the title says.
I'm an support main, typically playing Soraka, Janna, Zilean, Morgana, and various other "squishy" supports. Short of rushing an incredibly expensive (on a support budget) Zhonya's Hourglass, how in the world am I supposed to deal with a Zed that can wander down from mid-lane, ult me or my carry under tower, and leave?
And yes, I'm a bit salty, but I'm also curious, because I can see how popular Zed is and I really could use some advice against him.
General advice for squishy supports:
, 
(if enemy has at least one magic damage dealer),
. This should be your first item. Not upgrading to 
, not 
, certainly not 
. You need that full-river vision. That shit will save both your lane and your mid laner (possibly even your jungler). Get that vision down early, and maintain it. It's OK to delay Sightstone in some matchups. Never vs a Zed.Specific advice for the supports you've listed:
- E your ally/yourself when he ults. Aim the E so that it's centred in your escape path, so that Zed is forced to chase your ally through the E. Also, obviously, spam your Q/W/R.
- ult him away as soon as his ult lands, and be ready to Q him up as soon as he W back towards you. Obviously you should be sticking as close as possible to your ally, try to be behind your ally and not in front. Don't panic and use your Q too early, save it for after you've ulted him away. Janna is one of he biggest cock blocks for Zed, you literally can't die if you use your skills with the correct timing.
- use your speedup on whoever the Zed ults, and throw your bombs in the escape path. Once again, major cock block for Zed, you rarely even have to use your ult (use it if he gets a few too many hits off, but stay calm and assess the situation)
- this one can be tricky. You have lots of options. 1: Q Zed the moment he lands with his ult (this requires experience and perfect timing). 2: Ult him once he ults and walk towards where he ulted from. This will guarantee a stun (or force him away from you), but may put you in an undesirable position. 3: ult and run - Zed is more vulnerable to slows than people think, and if he keeps chasing you'll be in a good position for Q+W combo when he gets rooted.Overall, you can see the value of keeping your ult cooldown. If you're playing a passive support, play passive - hold onto your cooldowns and you'll be in a good position to avoid a Zed gank. Even without your ult, most of the supports can handle a Zed, but a lot relies on you controlling vision.
you ban him
Turn off shadows in your settings
steraks gage is basically the only assassin counter item right now besides zhonyas. unfortunately it doesnt really fit into the builds of the supports you say you play
Take exhaust and recommend sheild on adc. Take armor yellows and get the sight ward for hp? If he's not fed you are fine. If he's fed and Mia then expect to give up outer tower if its starting to get pushed and your jungler is not there to help defend. Keep an eye on your hp and summoners to know when it's best to just fall back and ping for mid to push and take tower there.
Soraka, Zilean and Morgana all have abilities that can lock down Zed as soon as he "exits" his ult. One binding/silence/stun and he's eating at least two turret shots. If the enemy botlane is pushing to set up a dive, then your adc will have to manage the wave better so that doesn't happen.
Janna/Morg/Raka/Zil have a great chance of surviving a Zed ult just with their kit alone
Sometimes it sucks to die but frankly it's much better that Zed just ults a support
