The border properties from Stacked “Borders” so this can be tested with Windows High Contrast Mode.

dropshadows are cool
a shadow border
shadow + outline
four shadows + one outline
border, shadow, outline
inner shadow + border
background-gradient + border
4 background gradients + 1 border
4 gradients + 1 translucent border
clipped backgrounds + border
border-image (missing)
Screen shot from Edge running Windows High Contrast Mode.