<button type="button" class="btn btn-primary">Blue</button>
<button type="button" class="btn btn-secondary">Grey</button>
<button type="button" class="btn btn-success">Green</button>
<button type="button" class="btn btn-danger">Red</button>
<button type="button" class="btn btn-warning">Yellow</button>
<button type="button" class="btn btn-info">Ligth blue</button>
<button type="button" class="btn btn-light">White</button>
<button type="button" class="btn btn-dark">Black</button>
<button type="button" class="btn btn-link">White with blue text</button>
.btn-primary, .btn-primary:hover, .btn-primary:active, .btn-primary:visited {
background-color: #8064A2 !important;
}
<!-- Bootstrap v5.0 -->
<button type="button" class="btn btn-primary">Primary</button>
<button type="button" class="btn btn-secondary">Secondary</button>
<button type="button" class="btn btn-success">Success</button>
<button type="button" class="btn btn-danger">Danger</button>
<button type="button" class="btn btn-warning">Warning</button>
<button type="button" class="btn btn-info">Info</button>
<button type="button" class="btn btn-light">Light</button>
<button type="button" class="btn btn-dark">Dark</button>
<button type="button" class="btn btn-link">Link</button>
<div class="btn-group" role="group" aria-label="Basic outlined example">
<button type="button" class="btn btn-outline-primary">Left</button>
<button type="button" class="btn btn-outline-primary">Middle</button>
<button type="button" class="btn btn-outline-primary">Right</button>
</div>
.btn-primary, .btn-primary:hover, .btn-primary:active, .btn-primary:visited {
background-color: #8064A2;
}