Category Template:Portal gathers all the " bricks " to make a portal.
Portals themselves are in Category:Portals.
The elements of portals which contain rules of graphics standards are in Category:Template:Graphic Charter
Watch out, you should not confuse with Category:portal links which includes all the banners of footer which send back to portals.
The following 53 pages are in this category, out of 53 total.