Well, besides the CYHMK riff, I would say the low guitarriff in the last few minuts of Fool to Cry. It's just incredible, and it made the song my favorite slow song.
There are a lot of songs that could and would qualify for this one...
As far as 'not the usual Stones' sounds...
Can't You Hear Me Knocking Slave Wild Horses Shattered certainly a few others...
'The Sound Of The Stones' Gimme Shelter Jumpin' Jack Flash Street Fighting Man Bitch Sweet Virginia Dancing With Mr D Crazy Mama She's So Cold Tie You Up Honky Tonk Women Love Is Strong Rough Justice Summer Romance a few others...ha ha ha ha
I'd go with his collective body of work in 1968-69, starting with Jumpin' Jack Flash, through Beggars Banquet, Let It Bleed and the Honky Tonk Women single and ending with Brown Sugar and Wild Horses.
a word should be said for a lot of his very beautiful acoustic playing on track... wild horses comes to mind; a twelve in there AND a six? whatever...just incredibly lovely