My friend develop new app and I want to introduce to you :
It is a free and very useful.
App name: Inbox - Attachment INBOX
For those who tries, searching for attachment inside mobile email's is frustrating task, usually you need to search one by one since name search is not working in most of the email clients.
With INBOX you can save your time and start searching for those local downloaded attachments in your device.
The application searches through your mail applications cache for attachments
and provides a great search engine for your attachment
Including filtering by type and search result ordering by: date, type, size, name
I hope you will find it very useful