“There’s some men wouldn’t look at a girl with a baby.” (Ken Follett, Fall of Giants)
There is a young student comes here some evenings. (James Joyce, Dubliners)
“That’s a smell could raise me out of a concrete grave.” (East of Eden)
“I guess it was Cal asked Lee.” (East of Eden)
I have a friend called me yesterday. (The Syntactic Phenomena of English)
There are sayings that subject relative pronouns can’t be omitted. But from the examples above on novels and a syntactic book, the construction seems not a rare case or wrong. What allows them the omission?