Of mine, Alice, previously mentioned, has kind of a thing for both him and, apparently, River. If he wants a pack of crazy-deadly, not speaking for River, but I think Len/River/Alice is awesome and hilarious. Nothing turns a big protective guy good faster than having two crazy-smart women to keep out of trouble. ;)

And Sabine I've already discussed.

Martha would hit this, yup.

Lee likes the look of him and he's smart and strong, so that'd be safe for his brain.

Leo, well, Leo likes attractive men with sound minds and sound bodies.