In case anyone is still looking for this functionality: I made an Android library that has this ability and much more, called ExpandableFab (https://github.com/nambicompany/expandable-fab).
The Material Design spec refers to this functionality as 'Speed Dial' and ExpandableFab implements it along with many additional features.
Nearly everything is customizable (colors, text, size, placement, margins, animations and more) and optional (don't need an Overlay, or FabOptions, or Labels, or icons, etc). Every property can be accessed or set through XML layouts or programmatically - whatever you prefer.
Written 100% in Kotlin but comes with full JavaDoc and KDoc (published API is well documented). Also comes with an example app so you can see different use cases with 0 coding.
Github: https://github.com/nambicompany/expandable-fab
Library website (w/ links to full documentation): https://nambicompany.github.io/expandable-fab/