I personally prefer beige background theme such as Novel theme of Terminal in Mac like below.
I checked Package list and also googled to find a beige color theme for Sublime but couldn’t get any. Any suggestions that I can install a beige background theme or just set the background color to beige? Thanks in advance!
You could always make your own. 
They are after all only xml files with various tags defined for different things.
Be sure you are checking TextMate theme’s also. Those work with ST. To change the background color, I’d recommend opening your color scheme (or the one you want to base yours on), copying the contents to a new file, saving it as .tmTheme in your Packages/User folder, then editing the colors you want. one of the keys in there should be background. You can change that to at least get you started. Oh and if you would rather work with JSON than xml, you can use github.com/facelessuser/SerializedDataConverter to replace it. This also supports yaml.
