I can give you another possible idea, monsoon is also an effect and its directly built to be this rain effect alongside clouds, but the issue is that, its not selectable. or so i think, you might wanna give it a try
I agree the Monsoon Effect is cool and would be great as an added effect for a cloud, it does not include any cloud though (although the waves of mist are appreciated)
first is this
Nebula , i can maybe give you a different colored version of this, but i'd imagine this is too much of the storm and no clouds are involved.
Looks more like a modified wisp than a cloud - too spherical, too sparkly, too symmetric... seems like editing this model would be too much work, might as well start from scratch
second is that, there is also the cloud special effect within the game, you know... the one that dragonhawkriders have as an ability. check if that's selectable and its comfortable to work with. i can also try and recolor that cloud effect for you to be more a mix of white and blue compared to light blue which looks like frost.
I have considered the Cloud ability - this effect is not selectable, but I did use this effect (in my only other map project that I published) as a ward, and I used an ingame ward model as the anchor for selecting, and the ward was not noticeable because Cloud is very dense. So, maybe you could get away with using a small ward or something; could also use a transparent model, like the Fairy, and just add all these effects to it...
Back to the cloud effect itself - the cloudiness of it is probably the closest thing we have to the effect I'd like, however the circular effects make it look unnatural, unless you are going for a Super-Cell, but you would still need cumulus and nimbus-looking things in there. Also it's blue... way too blue, lol...
(I looked at disease cloud too, not selectable, too transparent/small/fast moving, and green)
I suppose if there were some way to remove the circular effects and blue hue of cloud, paste a few of them together and make it selectable... it could work.
UPDATE: Alright, I think I found something reasonable - if a moderator would agree, we could call this solved...
1) I extracted Cloud of fog with RMPQ Extractor ( Abilities\Spells\Human\CloudOfFog\CloudOfFog.mdx )
2) I found the textures for this model, extracted those, and learned that they were colorless, so I
3) Opened up CloudOfFog.mdx in War3 Model Editor 1.07, went to the node manager, and set the blue hues to white and grey ones, which changes Cloud's appearance now.
4) Since I am not good at modeling, I decided to try to get around this with abilities and attachment points, so I:
5) Made an Ability based on the hidden ability "Sphere", put 6 sprites in there, and set it to CloudOfFog
6) Made an Ability based on Brilliance Aura, made the only target the Cloud itself, and set target attachment points to head, origin, overhead, chest, right foot, left foot
7) Set the model to Wisp, and made its permanent color light blue
8) Made another ability based off Immolation, allowed negative values in preferences, and made immolation into an AOE healing ability, and then used the Misfortune buff model for this... all the units were at max health, so it didn't seem to cause a crash....
What do you guys think? This looks awesome.