Bonus unlisted Gravity Head visitors now include a Better Half. Will there be others?

Already there's been a cameo/bonus/unlisted Gravity Head keg, already come and gone:

Marsha Mallow’s Malted Milk Stout 8% abv ... New Holland Collaboration Brew with City Provisions (Chicago)

Today another unexpected keg was delivered: Founders Curmudgeon's Better Half 11.9% abv

It will join the Founders third weekend wave on Friday, March 9, along with all listed Founders ales and both of Flat12's (Winter Cycle and Vulgar Display of Hops). Other bonus appearances still are expected, but it's too early to predict when they'll go on tap:

Against the Grain Oak-Aged Dilator Doppelbock circa 8% abv
Alltech Kentucky Bourbon Barrel Ale 8.2% abv

Flat12 Bierwerks Vulgar Display of Hops 9.7% abv

Schlenkerla Eiche (gravity-dispense) 8% abv

Sun King Dominator Doppelbock 8.1% abv
Sun King Isis Imperial IPA circa 9% abv

Three Floyds Topless Witch 9% abv
Three Floyds Stygian Darkness 9% abv