d3.interpolateRgb(a, b)

d3.interpolateHclLong(a, b)

d3.interpolateTransformCss(a, b) Returns an interpolator between the two 2D CSS transforms represented by a

d3.interpolateTransformSvg(a, b) Returns an interpolator between the two 2D SVG transforms represented by a

d3.interpolateCubehelix(a, b)

d3.interpolateRgbBasis(colors) Returns a uniform nonrational B-spline interpolator through the specified array of colors

d3.interpolate(a, b) Returns an interpolator between the two arbitrary values a and b. The interpolator

d3.interpolateDate(a, b) Returns an interpolator between the two

d3.interpolateNumber(a, b) Returns an interpolator between the two numbers a and b. The returned interpolator

d3.interpolateBasisClosed(values) Returns a uniform nonrational B-spline interpolator through the specified array of values