I highly recommend bloodwood for deep red accents, and it makes a great riser too. Very dense. Can be used as an I beam with softer more fragile or brittle woods too. Used in a footing adds strength to the riser too. Excellent wedge stock too.
Wenge is acceptable, and has very similar properties as paduke. Very stiff brittle wood. It adds a bit of zip to a bow limb using it in the core lams too.
I’ve never used spectra in a black color, but have use Chromaply. It has a higher density with thinner lams than spectra. More expensive too.
Ebony is too expensive to entertain cutting up for accent strips, but will work nicely if you have scraps you can slice up.
But you are right to avoid phenolic or glass accent lines in a wood riser. IMO.