Cards ile sadece CSS flex kullanarak yapabilirsiniz. 4.6 için;
<div class="card-columns">
<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title that wraps to a new line</h5>
<p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
</div>
</div>
<div class="card p-3">
<blockquote class="blockquote mb-0 card-body">
<p>A well-known quote, contained in a blockquote element.</p>
<footer class="blockquote-footer">
<small class="text-muted">
Someone famous in <cite title="Source Title">Source Title</cite>
</small>
</footer>
</blockquote>
</div>
<div class="card">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
<p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
</div>
</div>
<div class="card bg-primary text-white text-center p-3">
<blockquote class="blockquote mb-0">
<p>A well-known quote, contained in a blockquote element.</p>
<footer class="blockquote-footer text-white">
<small>
Someone famous in <cite title="Source Title">Source Title</cite>
</small>
</footer>
</blockquote>
</div>
<div class="card text-center">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This card has a regular title and short paragraphy of text below it.</p>
<p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
</div>
</div>
<div class="card">
<img src="..." class="card-img" alt="...">
</div>
<div class="card p-3 text-right">
<blockquote class="blockquote mb-0">
<p>A well-known quote, contained in a blockquote element.</p>
<footer class="blockquote-footer">
<small class="text-muted">
Someone famous in <cite title="Source Title">Source Title</cite>
</small>
</footer>
</blockquote>
</div>
<div class="card">
<div class="card-body">
<h5 class="card-title">Card title</h5>
<p class="card-text">This is another card with title and supporting text below. This card has some additional content to make it slightly taller overall.</p>
<p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
</div>
</div>
</div>