Ubuntu – Ubuntu themes directory

Xangua has answered my question. From his comments it appears that the Themes in the Ubuntu Repository isn't supported in the current 14.04 version of Ubuntu. Hopefully the developers will consider putting supported themes there so that the users can have a variety.

There might be other resources, but the only one that I found (so far) is the one linked by Xangua in the comments above. It might not be the most definitive, but it appears that the all the Themes in the gtk3 category are supported.

If this theory is correct, then anyone having problems with Ubuntu 14.04 and Themes can verify they are using a gtk3 type theme and it should work.

My next question (of which I'll spend time researching first) is to learn how to edit the title bar and borders of the gtk3 themes.

That's my only problem with the stock Ubuntu, is that you can't easily distinguish between the active and inactive windows and it's hard to tell (without window borders) where one window ends and the next begins, especially when having more than one terminal window on your screen.

The Themes in the Repository question is solved!

To install a new theme it would suffice to copy it to ~/.local/share/themes, and activate it using Unity Tweak Tool. Running update-alternatives won't be necessary.

Some themes are available via PPAs. Numix for example.

PPAs usually install them in /usr/share/themes and /usr/share/icons/, so it seems to me that your ~/icons folder is one created by yourself

Furthermore .$HOME/themes and $HOME/icons paths are deprecated and will not be read in future releases.