Angular scrollable mat-selection-list?

Simple CSS

mat-selection-list {
  max-height: 400px;
  overflow: auto;
}

StackBlitz Demo

By setting custom CSS properties?

CSS for fancy scroll bar which only supports Chrome browsers:

.custom-scroll-bar{
    height:70vh;
    overflow-y:scroll;
    overflow-x: hidden;
}

.custom-scroll-bar::-webkit-scrollbar{
    width: 5px;
}

.custom-scroll-bar::-webkit-scrollbar-thumb{
    background: rgba(0,0,0,.26);
}

For Firefox and Internet explorer just simply use:

.custom-scroll-bar{
    height:70vh;
    overflow-y:scroll;
}

HTML:

<mat-selection-list #shoes class="custom-scroll-bar">
  <mat-list-option *ngFor="let shoe of typesOfShoes">
    {{shoe}}
  </mat-list-option>
</mat-selection-list>

StackBlitz Example