Right now, under the “Subscriptions” section in the sidebar, communities with no icon are moved a bit to the left relative of communities with icons. This makes it seem like the other communities are a category of the one with no icon. Eg. In image below, Music Gear seems like it’s part of a category “Arduino”.
I suggest a placeholder image for the communities with no icons. Either that, or move them in line with the communities with icons while leaving the icon blank.
Edit: love the new update btw
Just put in a plain circle instead of a logo.