Here is a list based upon the unit I work on.

~2-3 days worth of clothes (we have a washer and dryer that we can use and limited space to store clothes and such
--no strings
--comfortable clothing
--comfortable shoes without laces or steel toe
--nothing with profanity, advertising drugs or alcohol or to revealing
~toiletries that you use
--our unit allows you to shave if one is on suicide checks they will need to have a staff member with them
--we have a locked belongings room that stores anything the patient can't have all the time. You can check them in and out as needed
~ for confidentiality reasons patients can't have the cell phones or any electronics with cameras...the phone can be locked up in case it is needed to check numbers, etc.
~ we recently started to allow small mp3 players once a person is off suicide checks unless the are without headphones then they can have them whenever.
~books, magazines, paper for drawing, cross word puzzle books, etc. Patients can't have notebooks with spiral bindings but we can rip pages out or whatever.
~a small amount of prepackaged snacks that are not in tin, medal, or glass containers.
~list of all prescriptions