4. White Blue and Orange Blockquote

blockquote {
font-family: Georgia, serif;
font-size: 16px;
font-style: italic;
width: 450px;
margin: 0.25em 0;
padding: 0.25em 40px;
line-height: 1.45;
position: relative;
color: #FFF;
border-left:5px solid #FF7F00;
background:#4b8baf;
}

blockquote cite {
color: #efefef;
font-size: 14px;
display: block;
margin-top: 5px;
}
 
blockquote cite:before {
content: "\2014 \2009";
}

6. Round Corner Blockquote

blockquote {
width: 450px;
background-color: #f9f9f9;
border: 1px solid #ccc;
border-radius: 6px;
box-shadow: 1px 1px 1px #ccc;
font-style: italic;
}
blockquote cite:before {
content: "\2014 \2009";
}

7. Using Gradient as Background for Blockquote

blockquote {
width: 450px;
color:#FFF;
background: #7d7e7d; /* Old browsers */
background: -moz-linear-gradient(top,  #7d7e7d 0%, #0e0e0e 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#7d7e7d), color-stop(100%,#0e0e0e)); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top,  #7d7e7d 0%,#0e0e0e 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top,  #7d7e7d 0%,#0e0e0e 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top,  #7d7e7d 0%,#0e0e0e 100%); /* IE10+ */
background: linear-gradient(to bottom,  #7d7e7d 0%,#0e0e0e 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#7d7e7d', endColorstr='#0e0e0e',GradientType=0 ); /* IE6-9 */
border: 1px solid #ccc;
border-radius: 6px;
box-shadow: 1px 1px 1px #ccc;
font-style: italic;
}
blockquote cite:before {
content: "\2014 \2009";
}

8. Blockquote with Background Pattern

blockquote {
width: 450px;
background-image:url('http://example.com/wp-content/themes/your-theme/images/lined_paper.png');
border: 1px solid #ccc;
box-shadow: 1px 1px 1px #ccc;
font-style: italic;
}
blockquote cite:before {
content: "\2014 \2009";
}

9. Using Multiple Images in Blockquote Background

blockquote {
width: 450px;
background-image:url('http://example.com/wp-content/themes/your-theme/images/lined_paper.png');
border: 1px solid #ccc;
box-shadow: 1px 1px 1px #ccc;
font-style: italic;
}
blockquote:before{
position:absolute;
margin-top:-20px;
margin-left:-20px;
content:url('http://example.com/wp-content/themes/your-theme/images/pin.png');
}
blockquote cite:before {
content: "\2014 \2009";
}

http://www.wpbeginner.com/wp-themes/how-to-customize-blockquotes-style-in-wordpress-themes/