There are a lot of different kinds of griffons in mythology, true most of them are just normal griffons made with different cat and birds parts but I'm not here to talk about them. Instead I'm talking about different kinds of griffons that are different enough to they could and should become different kind of griffon tribes in MLP canon, after all if ponies can have different tribes then others should get them too.

Demigriffon/Alce: They actually not really the same thing but close enough in looks that they would count as the same thing if they were ever made MLP canon. Alces in myth were wingless griffons who were smaller and more colorful, strangely they seem to be domestic as all myths had the as temple guardians. And not as spirits I would like to add but as flesh and blood creatures like some kind of big dog. Demigriffons (AKA the name they would use) is more of a modern culture term for wingless griffons and unlike Alces they are more like normal griffons without wings.

Keythong: These were wingless griffons that were cover in spikes, spines, barbs, quills, and sometimes even had horns. Unlike the Alces they were actually bigger then normal griffons, and they were all male, in fact in myths about them the normal griffons were the females of the specie. Funny thing Zeus was said to keep some around as pets and even breed them like how some breed dogs, which is why they are sometimes call the hounds of Zeus.

Opinicus: These were another kind of male griffon, but they had wings. In fact the only way there were different was the fact they had longer necks, no talons just four paws, camels tails, and they were said to be taller and skinnier. I did find one old myth that made it sound like they were more loners then normal griffons and only came around them to breed.

Axex: These griffons look almost just like normal griffons, but the were skinnier, shorter, had four paws instead of talons, and they were more colorful. There are some myths that make sound like they were nicer and also faster then normal griffons, but just a few.

Now between us I feel that demigriffons and keythongs are the only ones who have chance of becoming canon but I felt like the others needed to be talk about as well.

I would like to see the keythongs appear as antagonists waging war on Equestria; your description of their appearance creates the image of a classic villain race in my mind. Of course, the race itself would not be inherently evil, and most keythongs would be more than happy to be friends with ponies, but their rulers are only interested in conquering and enslaving them.

6850552
Not a bad idea but why would they still have different leaders then the rest of the griffons. The ponies united so wouldn't the griffons do the same

6850516
Can't say I'm familiar with most of these myths, although I do recognize the creatures' names and appearances.

6850585
Griffonstone doesn't really scream out "unified central government" to me, to be honest. In any case, the griffons and hippogriffs live separately, so there is precedent for having different griffs living in different nations and cultures.

6850585
That's up to you, but if I were writing a story about them, the regular griffons would have driven them away over their appearance.

6850691
Fair point but Griffobstone isn't the only town in the griffon kingdom, otherwise that what they would cal the kingdom instead of the griffon kingdom. Of course there is that one griffon city in Equestria territory which is where I think those griffons that always shows up at Equestria's leadership gathering cones from.

6850754
Why don't you then? It doesn't sound like a bad idea