This tech note has detailed information on powered off protection.
Why do I need a switch with powered off protection?
How do I tell if a TI signal switch has the powered off protection feature?
TI signal switches that have this feature will have a spec in the datasheet that states the leakage current with Vcc = 0V showing that the I/O signal path is Hi-Z.
example 1
Example 2
How do I find a switch with powered off protection?
TI currently has 97 devices with this feature and you can search for them on TI.com switch search tool by selecting the feature powered off protection.
Thank you,
Adam