eScope Error Handler takes care about errors (usually 404) when something is missing at front end. Plugin takes "alias" from old URL and ask database of articles if this alias exists. If it does, plugin redirect user to this article. If not, plugin calls com_search and puts words from alias to search. User don't get error 404 anymore. Just relevant results.
This Joomla! module displays categories from Phoca Gallery component. It can display the first picture of gallery as thumbnail, category name, category description and few other features. For better understanding check the demo. Set up choices and more information is in the documentation.
GForm is great Joomla component for creating guestionaires with many steps. It was developed to work writh Google Drive Spreadsheet forms.
GitHub Repo plugin embeds any public GitHub repository into your Joomla content.