Do we still not have a consensus on strange coin farming?
Not that I know of x.x
They come from tons of things though. Like, completing a public event can give mats including them. The package for having completed a public event can as well. Blue+ engrams can give them, crucible can give them, completing weekly strikes... I dunno if they can be a normal reward from strikes, never seen them there.
I feel like crucible could be one of the better options, since you can both get engrams and have a chance of strange coins dropping.