SECRET PACKAGES, SECRET GLYPHS
Clues:
I know not yet what Elminster hath shipped, but reckon at each store there’s naught but one. And whomsoever finds it, once equipped, should share its fruits with everyone. - @Immortal4tress
Resolutions:

TARRASQUE
- Tweeted first by @Estwilde
Rewards:
A souvenir Key and a hearty thank you from our heroes to those who shared this vital information:
@Chris70726
@rayirshien
@GammaViking
@djtigon
@Lecal
@JasonTDnDDM
@DMsWorkshop
Found at maCnarB Gaming

LIZARDFOLK
- Tweeted first by @Estwilde
Found at Aether Game Cafe

AURUMVORAX
- Tweeted first by @Estwilde
Firefly Toys & Games

GARGOYLE
- Tweeted first by @NickBWright
Game Kastle

GIANT CENTIPEDE
- Tweeted first by @CHofferCBus
Orc's Forge

MIMIC
- Tweeted first by @shield_bright
Black Knight Games

DRIDER
- Tweeted first by @Unkind_Froggy
Meeples Games

CYCLOPS
- Tweeted first by @Lecal
Red Castle Games

OCHRE JELLY
- Tweeted first by @Oukag
Beyond the Dungeon

OWLBEAR
- Tweeted first by @DMsWorkshop
A Muse N Games