HTML code and CSS rules for a wave like animation, more animation sources given in the comments

index.html

<!-- code taken from: https://blog.hubspot.com/website/css-loading-animation -->
<!-- code pen link: https://codepen.io/Bilal1909/pen/pobgJae -->

<!-- The style rules and the div element code should be kept together.
They've been kept seperately for just cleanliness -->

<div class="center">
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
    <div class="wave"></div>
</div>

style.css

.center {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #000;
}

.center:hover>* {
    background: red;
}

.wave {
    width: 5px;
    height: 100px;
    background: linear-gradient(45deg, cyan, #fff);
    margin: 10px;
    animation: wave 1s linear infinite;
    border-radius: 20px;
}

.wave:nth-child(2) {
    animation-delay: 0.1s;
}

.wave:nth-child(3) {
    animation-delay: 0.2s;
}

.wave:nth-child(4) {
    animation-delay: 0.3s;
}

.wave:nth-child(5) {
    animation-delay: 0.4s;
}

.wave:nth-child(6) {
    animation-delay: 0.5s;
}

.wave:nth-child(7) {
    animation-delay: 0.6s;
}

.wave:nth-child(8) {
    animation-delay: 0.7s;
}

.wave:nth-child(9) {
    animation-delay: 0.8s;
}

.wave:nth-child(10) {
    animation-delay: 0.9s;
}

@keyframes wave {
    0% {
        transform: scale(0);
    }
    50% {
        transform: scale(1);
    }
    100% {
        transform: scale(0);
    }
}

style.scss

// An scss version of style.css, because why not?

@use "sass:math";
.center {
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: #000;
    &:hover>* {
        background: red;
    }
}

.wave {
    width: 5px;
    height: 100px;
    background: linear-gradient(45deg, cyan, #fff);
    margin: 10px;
    animation: wave 1s linear infinite;
    border-radius: 20px;
    @for $i from 2 to 10 {
        &:nth-child(#{$i}) {
            animation-delay: #{math.div($i - 1, 10)}s;
        }
    }
}

@keyframes wave {
    0% {
        transform: scale(0);
    }
    50% {
        transform: scale(1);
    }
    100% {
        transform: scale(0);
    }
}