Is the Gelatinous ice cube familar official?

During the D&D celebration 2020 a new option for a familiar was revealed in the form of the image below.

I assumed it was official material because it was produced directly by wizards event though it does not appear in the the latest book (Tasha’s cauldron).

Is there any official word on if the 2020 celebrations material is legal in; adventure league, ordinary games or essentially homebrew?

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