A few more

[slackline]

None of these are my packages and it may be best to let the authors contribute there own but here are a couple of related packages, not all necessarily extensions, that I'm aware of...

• ggtern
• GGally
• gganimate
• ggthemes
• sjPlot also uses ggplot2 for such things as diagnostic plots of regression models, but may not be considered a true extension as its more a wrapper.

[scottshepard]

+1 for ggthemes

[omarbenites]

gganimate has been already added.
I agree with @scottshepard with ggthemes.

[Emaasit]

I have added ggthemes to develope branch. Will push it to master in a minute. @scottshepard & @omarbenites