Omnibox subreddit autocompletion. Just type 'r ' and explore 1648 of the biggest SFW subreddits.
This is a omnibox subreddit extension.
There are many like it, but this is mine.
Oh, also it has autocompletion.
The dataset is quite outdated, but I did not miss any of the subreddit I use to frequent. If anything you like is missing, just tell me, and I will add it.
Typing " img" after the subreddit name will bring you to the corresponding imgur.com gallery.
Subreddits you visit, but which are not known to the extensions are saved automatically. You can remove them again on the options page if the occasion calls for it.