>>48917028You nailed the strongest one besides Haxorus right there, Flygon - another one is Aggron, who is Tyranitar's rival. Charizard is a special one as not only a strong fit, but a starter mon as well. Others may come to my head eventually - it's a niche category so four entrants may be enough.
On a related note, there's the other category of psuedo legendaries, often overlooked - mons that can only be found and caught a limited number of times in the game and/or only obtained once through a handout or trade, giving them a legendary feel even if they're not strictly so. Snorlax and Porygon are strong examples. From there, you can fill in another tree of pseudo-pseudos, for Eevee and such - Eevee is actually a fairly common handout overall, but you still can't catch one in the wild.
And in the case of Beldum, we have a line that fits BOTH criteria of pseudo-legendary - the solid stat total, late evolutions, and locked to handouts.
Which leads me incidentally to say....
>>48917404... That the Beldum line are pseudos, and not pseudo-pseudos. They might break the dragon rule but they fit all of the other patterns very solidly.