As an open-source company, Magento does not come with many built-in themes. You can find themes of various third-party developers that are good looking and also mobile responsive. There are free themes available on these third-party sites but most are not for companies trying to eventually scale and reach new margins. You will find that most of the themes do come in packages and in these packages, you can find their own sets of advanced extensions. Choose a theme that mirrors your company image and offers the most valuable extensions for your brand. Because we are living in what it seems to be the prime years of the digital age, there is an increasingly huge market of mobile devices users to reach. If your company is not on mobile you may be losing thousands of dollars in revenue due to the gap of potential clients you are missing out on. Your company site must be mobile responsive and have the same aesthetic appeal as your desktop version. You do not need mobile users to go on your site and abandon it due to slow loading speed, massive images, and unformatted text. When searching for a Magento design it is imperative that you find a mobile-friendly design.