Shufflecake - ..."spiritual successor" of tools such as Truecrypt and Veracrypt....

https://shufflecake.net/
 
Shufflecake
 
Introduction
 
 Shufflecake is a tool for Linux that allows to create multiple hidden volumes on a storage device in such a way that it is very difficult, even under forensic inspection, to prove the existence of such volumes. ……… You can consider Shufflecake a "spiritual successor" of tools such as Truecrypt and Veracrypt, but vastly improved: it works natively on Linux, it supports any filesystem of choice, and can manage multiple nested volumes per device, so to make deniability of the existence of these partitions really plausible………..