acespritech

Are you looking for a way to create an upload form that automatically sends WordPress file uploads to your Dropbox? Using this Plugin you can easily integrate your Dropbox to your WordPress website. You can select maximum file size till your dropbox maximum upload size.
Features:- 
1 – Easy to connect form with Dropbox. 
2 – There is no file limit for upload. 
2 – Admin have short-code of form to display form in any page using it.
Shortcode:- [aspl_dropbox]

ASPL Dropbox File Upload

Another Best Plugin for Integrate Dropbox With Your Upload Form.

Denis Buka

This plugin allows you to upload single files or entire directories with subdirectories to your Dropbox account. You can use it for backup, synchronization or whatever uploading tasks you may have.
Features overview:
<ul>
<li>Upload entire directories with subdirectories to your Dropbox account. </li>
<li>Backup your entire site files by pointing to the WordPress installation directory. </li>
<li>Specify a Dropbox folder to which your files should be uploaded. If such folder doesn’t exist it will be created. </li>
</ul>
My other plugins:
<ul>
<li>Intuitive Navigation (https://wordpress.org/extend/plugins/intuitive-navigation/) </li>
<li>Generate Cache (https://wordpress.org/extend/plugins/generate-cache/) </li>
</ul>
Links: <a href="http://steamingkettle.net" rel="nofollow ugc">Steaming Kettle Website Design & Video Production Studio</a>

Drop in Dropbox

Upload single files or entire directories with subdirectories to your Dropbox account.

ASPL Dropbox File Upload vs Drop in Dropbox