Just some ideas for how to handle element loading feedback using animations. Each animation has only 1 or 2 elements, and most have no javascript. This is absolutely a work in progress.

Inline - Simple

code example

<div class="loading"></div>

@keyframes left-right {
    from {left: 0}
      to {left: calc(100% - 12px)}
}
.loading {
    width: 100%;
    height: 1px;
    border-bottom: 1px solid #C95B36;
    position: relative;
}

.loading::before {
    content:'';
    width: 12px;
    height: 12px;
    border-radius: 6px;
    background: #C95B36;
    position: absolute;
    left: 0;
    bottom: -7px;
    animation: linear alternate infinite 3s;
}

Inline with "spark"

code example

<div class="loading"></div>

@keyframes left-right {
    from {left: 0}
      to {left: calc(100% - 12px)}
}
.loading {
    width: 100%;
    height: 1px;
    border-bottom: 1px solid #C95B36;
    position: relative;
}

.loading::before {
    content:'';
    width: 4px;
    height: 4px;
    border-radius: 8px;
    background: white;
    position: absolute;
    left: 0;
    bottom: -3px;
    animation: left-right alternate infinite 3s;
    box-shadow: 0 0 10px 2px #C95B36;
}

Inline with "spark" on dark background.

code example

<div class="loading"></div>

@keyframes left-right {
    from {left: 0}
      to {left: calc(100% - 12px)}
}
.loading {
    width: 100%;
    height: 1px;
    border-bottom: 1px solid #B3F0F5;
    position: relative;
}

.loading::before {
    content:'';
    width: 4px;
    height: 4px;
    border-radius: 8px;
    background: white;
    position: absolute;
    left: 0;
    bottom: -3px;
    animation: left-right alternate infinite 3s;
    box-shadow: 0 0 10px 2px #B3F0F5;
}

Inline - Dots 1

code example

<div class="dots"><div class="dots inner"></div></div>

@keyframes sprite {
    0% {
        left: 0;
        transform: scale(.15);
        opacity: 0;
    }

    30% {
        opacity: 1;
    }

    75% {
        left: calc(100% - 40px);
        transform: scale(1);
        opacity: 1;
    }

    100% {
        left: 50%;
        transform: scale(3);
        opacity: 0;
    }
}

.dots {
    height: 20px;
    width: 100%;
    max-width: 300px;
    position: relative;
}

.dots.inner {
    margin: 0;
    width: 100%;
}


.dots::before,
.dots::after {
    content:'';
    width: 40px;
    height: 40px;
    border-radius: 20px;
    position: absolute;
    left: 0;
    top: -10px;
    opacity: 0;
    background: #C95B36;

    animation: sprite 4s ease-in infinite;
}

.dots::after        {animation-delay: .5s}
.dots.inner::before {animation-delay: 1s;}
.dots.inner::after  {animation-delay: 1.5s}

Circular - dial 1

code example

<div class="dial1"></div>

@keyframes rotator {
    from {transform: rotate(0deg)}
      to {transform: rotate(360deg)}
}

.dial1 {
    position: relative;
    width: 3rem;
    height: 3rem;
    background: var(--sienna);
    border-radius: 1.5rem;
    border-top-left-radius: 0;
    animation: rotator 3s infinite linear;

}

.dial1::after {
    content:'';
    position: absolute;
    top: -12px;
    left: -12px;;
    background: #C95B36;
    width: 8px;
    height: 8px;
    border-radius: 4px;
}

Circular - dial 2

code example

<div class="dial2"><div class="dial2-inner"></div></div>

@keyframes rotator {
    from {transform: rotate(0deg)}
      to {transform: rotate(360deg)}
}
.dial2 {
    position: relative;
    width: 3rem;
    height: 3rem;
    background: #C95B36;
    animation: rotator 3s infinite linear;
    border-radius: 2rem;
    border-top-left-radius: 0;
}

.dial2-inner {
    position: relative;
    left: -1.5rem;
    top: -1.5rem;
    width: 6rem;
    height: 6rem;
    border-radius: 4rem;
    animation: rotator 1.5s infinite linear reverse;
}

.dial2-inner::after {
    content: '';
    width: .6rem;
    height: .6rem;
    background: #C95B36;
    position: absolute;
    left: 0;
    top: 0;
    border-radius: 1rem;
}

Circular - dial 3

code example

<div class="dial3"></div>

@keyframes rotator {
    from {transform: rotate(0deg)}
      to {transform: rotate(360deg)}
}
.dial3 {
    position: relative;
    width: 3rem;
    height: 3rem;
}

.dial3::before,
.dial3::after {
    content: '';
    width: 3rem;
    height: 3rem;
    border: 1rem solid #C95B36;
    border-radius: 1.5rem;
    border-top-left-radius: 0;
    position: absolute;
    left: -1rem;
    top: -1rem;
    animation: rotator 5s infinite linear;
}

.dial3::after {
    animation: rotator 3s infinite linear reverse;
}

Circular - squares 1

code example

<div class="square1"><div class="square1-inner"></div></div>

@keyframes rotator {
    from {transform: rotate(0deg)}
      to {transform: rotate(360deg)}
}

.square1 {
    border: 1px solid #C95B36;
    width: 3rem;
    height: 3rem;
    position: relative;
    animation: rotator 3s infinite linear;

}
.square1-inner {
    border: 1px solid #C95B36;
    width: 6rem;
    height: 6rem;
    position: relative;
    left: -1.6rem;
    top: -1.6rem;
    animation: rotator 8s infinite linear reverse;
}

.square1-inner::before,
.square1-inner::after {
    content: '';
    width: 100%;
    height: 100%;
    position: absolute;
    left: 0;
    top: 0;
    border: 1px solid #C95B36;
    animation: rotator 3s infinite linear reverse;

}

.square1-inner::after {
    border-color: #C95B36;
    animation: rotator 6s infinite linear;
}