Finally earned the Ahead of the Curve achievement for completing The Jailer encounter in the Heroic Sepulcher of the First Ones raid! As a reward for doing so, I got my 563rd mount, Which is the Carinized Zerethsteed! 
Big thanks to my Guild - Ex Inferno, For helping me this done!
#512 Useable by one character - Battle Gargon Silessa
#693 - All the ZM mounts crafted.
#513 - Frightened Kodo (Finally!)
Nice. Thatās one of the best mounts in the game.
601 Bonesewn Fleshroc
602 Dauntless Duskrunner
603 Gruesome Flayedwing
604 Pale Acidmaw
605 Silvertip Dredwing - the last 4 here coming from Stichmasters exalted and 20k anima making it a rare 4 mount day
Just got my 564th usable mount in-game for my main. My newest mount is the Loyal Gorger!
#514 Enchanted Dreamlight Runestag
#515 Silky Shimmermoth
#516 Winterborn Runestag
#517 Umbral Scythehorn
\o/
#518 Phalynx of Courage
#519 Eternal Phalynx of Courage
#520 Enchanted Winterborn Runestag
On a roll by just doing some campaigns!
(Had to edit this twice cause canāt post more than three consecutive posts. oof)
#719 - Pale Regal Cervid
#720 - Carcinized Zerethsteed
#721 - Cartel Masterās Gearglider (first kill)
Collection bot says I have 720 now instead, Iām wondering if that +1 we all got a few weeks ago was fixed.
#521 Pestilent Necroray
He hasnāt hatched yet but heās my final necroray egg!
#522 Vibrant Flutterwing
I wouldnāt normally update when I obtain only one mount but I just bought Vengeance from M Sylvanas and Iām super excited.
mount # 606
#606 - Battle-Bound Warhound
#607 - Tangled Dreamweaver
#608 - Nether-Gorged Greatwyrm
#609 - Deepstar Aurelid
#610 - Carcinized Zerethsteed
Edit: Just checked and yeah something was fixed. Iām at 607 instead of 610 where my notes say I should be.
Soā¦ 607? 610? Iāll go with āa lot.ā This could all be solved by giving our statistic back, BLIZZARD 
Being off by 3 seems odd, maybe the armory hadnāt updated yet for the bot? I find it takes a while before the the info is updated properly for external tracking.
Iāll check again later to see if it updated because youāre right, I shouldnāt be off that much.
Iāve found in the past a nice logout and 15min would be all thats required but these days my Simplearmory doesnāt even register the updated mounts until the next day. Iāll wait hours and check and still nothing.
Try again today Iām sure youāll get a better number, but probably only 609, I think we lost our +1
Just received my 565th mount in-game and it was from the Tormentorās Event that spawns every (2) hours. This mount also took me 42 attempts to finally obtain!
My newest mount is the Hand of Bahmethra!
It did finally update. Iām at 609, which is exactly where I should be since I remember I gained a mount for some odd reason.
#523 Silverwind Larion - Finally just bit the bullet and did the dungeons.
#524 Nether-Gorged Greatwyrm \o/