Some is not needed in those, and in fact, indicates a "smallness" in the quantity.
It was foggy this morning = There was fog this morning.
It was a little foggy this morning = There was some fog this morning.
There are wolves in that forest=Wolves exist in that forest=That forest has wolves in it (so be careful!)
There are some wolves in that forsest=That forest has a few wolves.
I wouldn't use the contraction There're.
They are = They're is pronounced like "there."
In speech, we may slur together "there're" but it's not one that's commonly written.