Worked for me over two accounts on EU. Only opened standard packs 

After 4x packs of Un'Goro I get Voraxx, 7x packs of Geringontzan i get Kun and 3x packs of Old Gods i get Golden Anomalus. OP

I just tried on my account (NA). Got a legendary on pack 5 of Un'Goro and no others. 

Meanwhile my friend came online when I told him about it and he got a classic, old gods, and Un'Goro legendary within the first ten packs of those sets. 

Worked for me bought 10 of each

Unguro  golden waygate, andclutch mother 

Gadgetzan patches

Old gods golden ysharj and n zoth

Classic golden jarraxus 

This is legit and also got a  of golden epics

Just tested:

Un'Goro - 4th pack (but my pity timer was around 20 already)

WotoG - 7th pack (pity timer was reset)

MSoG - 5th pack (pity timer was reset)

Classic - 8th pack (pity timer was close to zero)

So, worked for me it seems :)

My friend just opened 15 packs and got nothing 

Igual just opened 3 leg un one day...You should try if you have the gold

Classic (14) - nothing

Old gods(4) - sogoth the slitherer

Mean streets (9) - white eyes

Ungoro (1)- clutchmother zavas

Worked for all the standard packs except classic. This could be because I accidentally backed out of the store to the main screen. Good luck to everyone this is legit.

Xaril poison mind.   Caverns below. Genzo the shark

Here's what I posted on the HS forums:

Okay, I just tried:

10 Packs of JtU: Paladin Quest (...)
6 Packs of MSoG: Golden Warlock Legendary (Highlander)
7 Packs of Old Gods: Anomalus

Edit: Just tried Classic --- failed after 10 packs.

Got Warrior quest on 6th pack in Un goro. Got nothing on 10 packs classic. 

Just a coincidence Imo. Save your gold for the expansion 

It works in the first 10 packs of each set, confirmed by a long time player. I haven't tried for GvG and TGT, but 15$ well invested in Yogg-Saron Saron and King (meh) Mukkla!

OK, I'm also having extraordinary luck for the first time ever. I just bought ten classic packs with gold and pulled legendaries from three in a row (Pat Nagle, meh; Edwin VanCleef and Alexstrasza? Hell yeah).

I even had great luck on rares; only 2 of 12 were duplicates. And hell, I'm even getting the exact epics that I want: Snake Trap from my classics, and a Vilespine Slayer on my first Un'goro pack! Merry Christmas, everyone!

Oh, and there's a Pyros with my Un'goro pity timer at 28. And my first MSOG pack just yielded a Knuckles. Aaand, there's Soggoth the Slitherer in my third Old Gods pack.

Thanks, Blizzard. I had some pretty rough luck with my Un'Goro packs. This makes up for it.

does anyone knows if the counter restarts after you get a legendary? If I got an ungoro legendary at the 2nd pack, will I get another one in the next 10?

I had five packs each of Un'Goro and Classic stockpiled for the change.

Second pack of classic, Cenarius.

First pack of Un'Goro, my first golden ... The Voraxx.

Second pack of Un'Goro, Clutchmother Zavas.

Must be karma in getting the latter two, as Un'Goro awarded me the quests for Paladin and Warlock in the first 10 packs on opening day AND gave me duplicates of both. Grr. Sucks that so far nothing in Paladin KoFT previews seems aimed at improving that quest, while warlock has a tepid legendary but not much else supporting discolock.

/gotta fight the temptation to blow money on the other expansions

//wonder if Blizzard did this intentionally, hoping word of mouth would get extra sales and coin stockpiles reduced

I did open some pack that i got saved:

9 ungoro= 2 legendaries

1 Old gods= 1 Legendary

9 Classics= 1 Golden legendary

with the heat of the moment i bought another three classic packs = One more legendary

I usde my arena tickets an some gold in another two acounts to got like 5 packs in one, two in another:  A legendary in the one wiht 5 Packs, none int he one with 7 packs.

Im tempted to go back to my main account to try it again with some gadgetzan packs....

Still working.

I've opened many of these packs before, but tonight...

ungoro 3 packs = legendary

mean streets 10 packs = legendary

old gods 10 packs = legendary

classic 10 packs = NO legendary (not sure what's up there)

It just worked for me.  I'm a NA region player, been playing since open beta.  I think I've missed less than 10 dailies total since the game started  (just to let you know how much I play).  I've been saving packs since the announcement, here's my breakdown.

Classic: 23 until next Legendary...  (3 already saved), Gruel on 2nd pack

Old Gods: 23 until next Legendary... (Bought with gold) Princess huhuran on 7th pack

MSG: 20 until next Legendary...  (Bought with gold) Kruul on 4th pack

UNG: 31 until next Legendary (5 already saved, rest bought with gold), Ozruk on 9th pack

Overall, I think the drop rates seem better as well.  More rares, epics, and goldens than normal.

Thanks everyone for keeping this thread going and giving me the courage to try while hoarding for KFT.  I hope this helps someone!

Wow!!!!!!!!!!!! ½½½!!!½½½!!!

Opened 3 classic packs - Got Procphet Velen (didnt have) ...
Ediit... opened 2 more... got Antonidas... (didnt have)

Opened 6 Un'Goro - Got Lyra (didn't have)

 10 MeanStreets - Got Wrathion (didn't have)

3 Old Gods - Got Yogg and Y'sharj (didn't have any)

I am not sure where I were on the pity timer, but I certainly was not high on any of them. Mean streets was at 0. Playing on EU server.

It works, but not for classic packs.

Worked for me as well, 

1 WoG: Huhuran

8 MSG: 2/2 Warrior guy

5 Ungoro: Pyros

7 Classic: Onyxia

Guy from my friendlist opened 30 ungoro he had saved and got like 5 legendaries