I thought he would come: Yes it indicates both probability and intention. I heard you had an accident. This is preferred, but note that there should be no comma within this sentence. This is actually not DEFINITE knowledge that he had an accident, only an indication of having heard such an account. It allows for the possibility that what we heard was in fact wrong. Of the last three, the latter two are correct. The first doesn’t agree in tense; thought is past tense, “is” is present tense.