Hi, have you considered adding a Meteor icon for the .meteor folder and also for client and server folders?
I tried to create a meteor folder icon, but it does not look very nice. So I'll postpone it for now. I haven't thought about client and server folder icons yet, but I will. I think that should be possible. Let's wait and see ;)
Added client and server folder icons:

Really cool :D
I personally tried to create a meteor folder icon, but i was unable to get something correct for the size.
The logo was an unrecognizable pixel porridge
.meteor will be difficult to theme, but what about an icon for startup folder ?
@Guema Yes, .meteor as a folder icon does not look very nice. I was wondering for what purposes do you use the startup folder? I think it's not very common. Maybe you can customize the folder associations in your user settings like this:
"material-icon-theme.folders.associations": {
"startup": "scripts"
}
You can pick any of the other folder icons that are shown in this image for that.
startup is an recommended convention in meteor apps.
It's a convention for store redundant initialisations because meteor is mostly module based.
(This is why i talk about it in this ticket)
Node.js is also module based and for the same reason (redundant initializations) I use a startup folder. So I think a startupfolder icon would be awesome to have.
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Added client and server folder icons: