bd Widget Framework is an excellent add on that makes changing the side blocks of your entire forum very simple. It's also very easy to work with which is why I've decided to make some widgets for it.
All the widgets can be seen on this site:
Similar threads (when viewing a thread, if similar threads are found),
Attachment Slide show (displays the most recent attachments as a slideshow, visible on the forum index here),
User Cloud (find users based on certain criteria and display them as a tag cloud, not done yet)
. More Coming Soon,Make suggestions.
Attachment Slide Show
Display the {x} most recent attachments as a slide show. Only attachments that are visible to the visitor will be displayed.
User Cloud
Display in one of 3 views, avatar cloud (animated), avatar cloud (standard), or a list, a group of user's based on options you select. You can choose to select any number of users, sorted by most likes, most messages, most trophy points, most recently registered, or most recent activity.
Similar Threads
Can only be used in the "thread_view" position. Breaks the title of the thread currently being viewed into words and searched these words against other threads titles to find possible matches.
Users That Viewed Thread
Display all the users that viewed the thread currently being looked at. The same views as the user cloud are used here.