This mod adds a block you can place midair or in fluids to help build in the sky or in water. You can instantly break it without the need of a tool, and it will go directly back into your inventory after breaking.
The mod is a continuation of Angel Block, which ported the feature from Extra Utilities, if you want versions from 1.14 to 1.16, look at Angel Block. The Code is based on Placement Utilities, if you want things like Temporary Blocks, or you would like to place all Blocks like the Angel Block with extended reach, look there (currently only available for Forge).
Recipe: