Can there be portals in the Astral Plane that lead to the Elemental Planes?

In the spell description of Astral Projection (PHB pg 215) it indicates the following :

Your astral form can freely travel through the Astral Plane and can pass through portals there to any other plane.

However, in the Astral Color Pools table (DMG pg 47) there are no color pools leading to the the Elemental Planes (or the Shadowfell or Feywild). The description of "color pools" refers to them as "gateways".

Finally, in the description of relevant planar travel spells (DMG pg 46) it indicates the following :

And the astral projection spell lets adventurers project themselves into the Astral Plane and from there travel to the Outer Planes.

Accordingly, can there be portals in the Astral Plane that lead to the Elemental Planes?