ChuckH
Ban IP Address/Range for 1.5
This simple plugin installs into your 1.5 site to blacklist or whitelist IP addresses and ranges for either the administrator or the site. The settings can be used interchangeably so the administrator can be set to white list mode and the site can be set ...
GCalendar 
GCalendar connects google calendars with your joomla powered web site. It is a suite of extensions to show your google calendar events smooth integrated into joomla. Easy configuration, CSS based customization and performance gains through AJAX and advan ...
GuardXT
GuardXT performs some health checks on your Joomla site. The "heart" of GuardXT is a file system check (best scheduled as a cron job), that regularly monitors changes of your files. Additionally various security checks may be performed (e.g. check Joomla ...