Meg Robichaud (illustrator at Shopify) wrote a nice piece on the different types of illustrations both for product and marketing (~brand). Icons, spot, scene and editorial illustrations get introduced and looked at both from product and brand perspective. Here is the gist of it:
Icons in product: power and available features
Icons in brand: navigation, to inject some branding
Spot in product: to be read, “hey look at this thing” and just straight up show you the thing
Spot in brand: marketing illustrations say “holy butts did you know about this tho??”, feature call outs
Scene in product: explain complicated ideas, mainly in onboarding
Scene in brand: explain, but also why is it relevant, “how it works”
Editorial: complement the content, capture the mood
I also liked her checklist on icon design consistency:
– Corner radius
– Line treatment (stroke weight; cap treatment; ect)
– Overall weight (ie. if each pixel was a drop of paint, would they all make more or less the same tone when you mix them together?)
– Use of colour
– Are they all tilted (or not tilted) at the same angle?
– Do they handle connecting pieces similarly (either by leaving spaces or by finding ways to connect multiple objects)?
– Do they have either relatively similar silhouettes (eg. all contained in circles) or relatively unique silhouettes?
If you’re this far in reading, read the whole thing.