Panel A: Transparent washes with blooms and paper texture \(⇒\) Watercolour.
Panel B: Waxy, textural strokes and flat fills \(⇒\) Crayon.
Panel C: Opaque, fast-dry layers with matte look \(⇒\) Acrylic.
Panel D: Rich blending and glazing depth \(⇒\) Oil Paint.
Therefore the sequence \(A\!-\!D\) is \(\boxed{\text{Watercolour, Crayon, Acrylic, Oil Paint}}\).