Different colour for new tabs in iTerm2
With iTerm open, go to the iterm2 menu item and select preferences. From preferences, you'll get a panel that looks like the image below.



From this image select the Profiles icon in the top row. This shows the following panel.



From this panel click on colors that brings up this final panel.



you can see in this panel there is a checkbox labeled tab color. This allows you to set your tab color. All tabs opened now will use this new color.