As per the information bulletin released by the CBSE, he/she will bring only the following at the examination center:

Admit Card with passport size photograph affixed on it.
One passport size photograph to be affixed on attendance sheet
DRESS CODE: The candidates are instructed to follow the following dress code while appearing for NEET(UG):

Light clothes with half sleeves not having big buttons, brooch/badge, flower etc. with Salwar/Trouser.
Slippers, sandals with low heels and not the shoes.

Things which are not allowed:

Any stationery item like textual material (printed or written), bits of papers, Geometry/Pencil Box, Plastic Pouch, Calculator, Pen, Scale, Writing Pad, Pen Drives, Eraser, Calculator, Log Table, Electronic Pen/Scanner etc.
Any communication device like Mobile Phone, Bluetooth, Earphones, Microphone, Pager, Health Band etc.
Other items like Wallet, Goggles, Handbags, Belt, Cap etc.
All ornaments like Ring, Earrings, Nose-pin, Chain/Necklace, Pendants, Badge and Brooch etc.
Any Watch/Wrist Watch, Bracelet, Camera, etc.
Any metallic item
Any eatable item opened or packed, water bottle etc.

Hope it was helpful..
For any doubts check the official NEET WEBSITE
ALL THE BEST.......