K1 — Original: solid color fill
K4 — Monochrome dark grey
K5 — Color fill + drop shadow
K6 — Color fill + diffuse glow
K7 — 2-tone gradient fill
K8 — Color fill + white ring
K9 — Color fill + soft color ring
K10 — Color fill + lift + shadow
K11 — Color fill + hue-rotating glow
K12 — Color fill + slow spinning rainbow ring
K13 — Color fill + breathing pulse
K14 — Color fill + elastic overshoot
K15 — Color fill + wide radial spread
K16 — Warm palette: teal / amber
K17 — Neon: electric blue / hot pink
K19 — Color fill + dark icon
K20 — Color fill + ripple ring