First up, we have Diverse Guards Skyrim: http://skyrim.nexusmods.com/mods/8943
This adds more city guard and soldier NPCs for wider variety, particularly if you are using an open-face mod. Furthermore, it adds some female NPCs to the guard complement found in Whiterun, Solitude and Markarth, and the Imperial Army.
Next, we have Diverse Muscle Tones: (Also found on the nexus, but not linked to from here because while it is not an advlt mod per-se, some of the images in the mod page are.)
This increases visual diversity amongst female NPCs by using a variety of body-mod normal-map textures to simulate differing levels of muscle tone. The idea is that fighty melee types or people who do a hard physical job (eg, blacksmithing) look the most muscular, with various other types of lifestyle or occupation being more or less muscular than the vanilla baseline.
Note that the normal-map texture resources are used with permission.
Finally, there is Consistent Older People: http://skyrim.nexusmods.com/mods/19730
Something that has always niggled me is that some NPCs have old bodies to match old faces, while others (such as Angeline Morrard) have an elderly face but an otherwise normal, youthful body. Some might have changed this by making the fake-old NPCs look younger, but as I am a grump-powered curmudgeon I decided to make their bodies match their faces!
Have fun, people
