I'm not sure about the mechanic, but I was looking for a way of doing tribal that allows you to mix two types, but not just "any good creatures". If you didn't just make "goblin decks" but "goblin and elf decks" or "merfolk and giant decks" etc there could be a lot more variety in tribal.

Lorwyn/Shadowmoor tried to do this a bit, but it seemed like you'd end up with a patchwork alliance across several creature types, not really rewarded for focussing on two.

I wasn't sure how to do that mechanically, though. Ideally I wanted a wording that could replace "all goblins" with "all goblins and something", but as a default deck-building choice, not as an obscure build-around me enchantment you need to trick out. Make you declare two creature types up-front before the start of the game? Key off "the most common two creature types"? Require only two types in deck? Here it turns off if you mix and match too much which I don't like if it happens, but I like if it leads to people deck-building without it. But that's not going to be good in limited.

It could allow you to choose on ETB like adaptive automaton, but then it leads to "play lords with evasion creatures of any type".

Goblin allied doesn't actually have anything to do with goblins, then? That's really confusing.

So let me get this straight. This is in play. It's a 3/2 with haste, yes? Okay, moving on...

If I play Elvish Warrior, it gets +1/+1 and gains haste because it shares a type with the Goblin Alliance Leader. Right? And then if I play an Arbor Elf it gets +1/+1 and haste because it shares a type with Elvish Warrior and Elvish Warrior shares a type with the GAL. Right? But if the Elvish Warrior leaves the table, the Arbor Elf loses the bonus because the connecting piece is now missing?

I really like the mechanic, but it's pretty damn confoosing. I'd say it isn't a common ability, but commons may work if they're enter the battlefield triggers, since it would only check the one time. I think the reminder text probably needs a whole extra sentence in order to fully spell this out, though. Oh, and dude is right. This should just say "creatures allied with GAL..."

Unless I'm completely off base and you plan on introducing cards that look like this:

Savage Elf
­
Creature - Elf Barbarian
Goblin Allied
1/2

...or in other words, creatures with rider text with no value to hook up to other cards (It's just a 1/2 unless you have a GAL in play. Then it's a 2/3 with haste.) Personally, I think that's another great idea except for the fact that 'Magic doesn't really do that'. 'They do now' seems like a valid answer, though. And I suppose people would play the cards exactly as you'd want. They'd ignore 'Goblin aligned' until they either figured it out, or looked it up. Then they'd know. They'd never play it wrong, though.

I think the INTENTION is simple. Like, if you have this, some goblins, and some elves. They all get the bonus. If you have this, some goblins, an elf, and a giant, only the goblins get the bonus.

But I can't think of a wording which is simple and concise. If there is any decent wording, it's likely completely different.

Would people understand what the card did if it said "When this ETBs, choose a creature type. Other goblin creatures and other creatures of that type get +1/+1 and haste." even if you thought it was too wordy?

I don't like the idea that "goblin allied" means "share a creature type". Presumably that's also what "elf allied" and "kavu allied" mean. Reminiscent of the bad old days when five Wolves with "bands with Kavu" could all attack together in a band.

I prefer Jack's wording.

And if you don't like a generic lord, what about if you have to choose the creature type you have the most of on the field?

So you want this: "Other Goblin creatures you control get +1/+1 and gain haste.

Alliance - As long as all non-Goblin creatures you control share a creature type, they all get +1/+1 and have haste." ?

Or do it like that: "As ~ enters the battlefield, choose a creature type other than Goblin.

Other creatures that are Goblins and/or the chosen creature type get +1/+1 and have haste."