[VanimaEdhel]

A better question would be, "Which Myths and Stories Could Not Be Connected Somehow to Basic Plotlines and/or Themes That Can Be Found Within The Silmarillion, The Lord of the Rings, and Other Tolkien Stories?" If you look within The Silmarillion, you can find many things that are reminiscent of other such religious texts and myths, such as The Bible and Greek and Roman Mythology.

Now remember, however, JRR Tolkien claimed to hate allusion, so, most likely, although he would have most certainly known that what he was referring to was related in some way to another tale, he did not do it in the hopes of having someone say, "Oh! The beginning sounds a lot like Genesis!" (That "someone" being me, of course). He wanted to create Folklore for England, so of course the ideas he would create would be much like those of the Folklore of other cultures. If you look at these other stories and myths, they parallel in many fields. Many myths are similar in concept and, of course, moral.

So, while Tolkien most likely did not go out of his way to find Mythology and Folklore to parallel Middle Earth on, yes: there are parallels to Irish Mythology, Greek Mythology, Roman Mythology, Norse Mythology, and even Biblical tales, if you look at the lands, people, and stories he created.

I probably did not have to write that much, but I hope that helps you in some way...