The most difficult alternative

Nature has very little to offer in terms of Void Dragons. I recently tried playing a Nature build focused on Chaos, taking a Void Dragon + Chaos Knight + Druid, with the intention of later adding a second Chaos Knight, but I quickly realized that it would be extremely difficult to succeed. The problem is that the Void Dragon's damage is fixed due to its magic, and their chances in melee combat are slim. So, for example, when a Void Dragon hits a peasant with a lightning bolt, it always deals 13 damage (67+67=134), while a Phoenix, with Tactics, can deal around 500 damage(!). Another important advantage is that Phoenixes can be used to keep any neutral troops away from heroes. Void Dragons can't do this because they need to maintain distance from the enemy. Therefore, Void Dragons need either Manticores or Griffins, which in turn require the infamous Tactics skill.

Vampires still depend on the skill.

Only on Whirlwinds.

Order... Djinns.

With triple strike, Nagas are very strong. It's also quite easy to clear neutral creatures with them; just heal them in time and, if possible, buff them with things like "Flight," "Bless," and "Armor," etc.

Ifrits... What's the point of their fire resistance?

Ifrits have high speed and attack. I've used them a couple of times as cannon fodder to absorb attacks; I remember successfully taking down about 6 Bone Dragons with 1+1+1 Ifrits, 1 Black Dragon, a hero with Tactics, and two Chaos Knights (they weren't very effective with magic).

There are often not enough resources for Angels.

There are enough resources, but it's not always possible to build them quickly, unless there's a Magic Garden nearby, or several piles of crystals on the map. For cavalry, it's better to take Crusaders; firstly, they will absorb attacks in difficult battles, and secondly, Champions require a Stable + Order of Paladins – the latter is also needed for Crusaders, i.e., reducing the time to build to level 4. (Monks also require an Abbey)