How to hide/disable tables without dropping them to check redundancy?

A couple of other options are to just rename the tables, or if they have clustered indexes, you can disable the clustered index.

Is there any other way to achieve the same(tables cannot be used anymore) without dropping them?

A schema change is a very fast operation - just metadata change is required. The original idea I got was from Aaron Bertrand's blog - Schema Switch-A-Roo.

You can follow the steps from my answer here

Obviously there are other methods like sp_rename N'old table', N'new table' or just deny permissions to the table.

Remove the permissions on the table from the Role(s)/ Group(s)/ Account(s) that [might] be using it.

If anything blows up, put them back [quickly].

Hint: Using a script to do make these changes would be a really, really Good Idea.