I don't believe Bonsai stores anything on sdcard other than what stock OS has going to sdcard normally which is very little aside from pics/video under the folder DCIM.
i am trying to figure out which of these folder would be safe to delete. see screenshot below.
Click to view quoted image
You actually have one of the more organized and cleaner looking sdcard's that I've seen.. hahah, you should see mine...
Mine is a mess only because I carry around most of the ROMs/kernels available so I can change up at a moments notice... Then there is all the theme work that my partner ZiggSvo and I have done too..LOL! Mine is decent now, but you should have seen mine before I decided to move everything off, format the sd card, then put everything back on! Took forever in CWM to flash, just because of all the folders I had to look thru just to find the roms, haha. Quite pretty and organized now, tho