Led Zeppelin does not get enough credit for their diversity of Blues grass influence vs. harder rock songs they are well known for, even though they are rated as the best Rock band of the earlier 70's era, and possibly edging out The Beatles of the 60's if that's even possible!
George Harrison was friends with Jonh Bonham and asked Bonham why Led Zeppelin did not do Ballads, That song Jimmy wrote by George Harrison's influence was, "The Rain Song" which I believe has already been Quoted in this thread and is one of my fav's. So, I won't list it again. IF not for George Harrison's comment to "Bonnzo" The Rain song, would not exist.
This is also one of my fav's among many other Led Zeppelin songs, they had many others that were not big top hits and not hard rock. like Down By the Seaside, ect.
Down by the seaside
See the boats go sailin'
Can the people hear
What the little fish are sayin'
Led Zeppelin, Jimmy Page / Robert Plant, Physical Graffiti
Then as it was, then again it will be
And though the course may change sometimes
Rivers always reach the sea
Blind stars of fortune, each have several rays
On the wings of maybe, down in birds of prey
Kind of makes me feel sometimes, didn't have to grow
But as the eagle leaves the nest, it's got so far to go
Changes fill my time, baby, that's alright with me
In the midst I think of you, and how it used to be
10 Years Gone, Led Zeppelin, Jimmy Page / Robert Plant, Physical Graffiti. "One of the most under rated songs of Their career."
Close the door, put out the light
No, they won't be home tonight
The snow falls hard and don't you know?
The winds of Thor are blowing cold
They're wearing steel that's bright and true
They carry news that must get through, oh
They choose the path where no-one goes
They hold no quarter
No Quarter, Led Zeppelin, Jimmy Page / Robert Plant/ Jonh Paul Jones, Houses of the Holy