Chaos structures.

Ruslan, you're confusing me. Dima Stranger brought 300 ballistas to the PS and also put on a show. ;) However, this is more of an exotic option than a guaranteed one. It's not easy to find Town Portal creatures for Chaos, and you need to gather quite a few Hydras to make it interesting (let's forget about PowerSpot and Bizarro :D).

Regarding speed. And what will you fly on? On Ifrits without Hydras? Then it's unclear what you'll fight with. Chaos doesn't have anything to rush with.

And yet, PowerSpot is a great example :) Hydras are simply dominant there, and if you notice them in one or two markets, there will be no shortage of them, plus the movement speed of the monsters isn't that important there. And I've never tried flying on the Spot; I prefer to walk or ride a horse. :)
And if we're talking about guaranteed options, the most guaranteed option on the Spot is what's sold in the market. If you try hard and there are no Black Dragons in any of the markets, even if they're grazing among the neutrals, you'll only manage to gather a few in 20 days. That's not enough for the Spot.
I agree that gathering hundreds of ballistas, gargoyles, pikemen, mages, etc., is exotic, but I've always liked gathering meat from the market from level 4.

It's more difficult to manage with Hydras on Bizarro; after all, faster monsters are more important there because the map is usually played on Advance, which makes it easy to clear.

Of course, if you remember maps like Ironman, then Black Dragons are everything for us. :)