People are forever concocting classes that replace the standard ones: the present author produced an ukart class that used the sober package, and a few British-specific things (such as appear in the babel package’s British-english specialisation) in the 1980s, which is still occasionally used.
Similar public efforts were available well back in the days of LaTeX 2.09: a notable example, whose pleasing designs seem not to have changed much over all that time, is the ntgclass bundle. Each of the standard classes is replaced by a selection of classes, named in Dutch, sometimes with a single numeric digit attached. So we have classes artikel2, rapport1, boek3 and brief. These classes are moderately well documented in English.
The KOMA-script bundle (classes named scr...) are a strong current contender. They are actively supported and are subject to sensitive development; they are comprehensive in their coverage of significant typesetting issues; they produce good-looking output and they are well documented in both English (scrguien in the distribution) and German (scrguide in the distribution).
The other comparable class is memoir. This aims to replace book and report classes directly, and (like KOMA-script) is comprehensive in its coverage of small issues. Memoir’s documentation (memman) is very highly spoken of, and its lengthy introductory section is regularly recommended as a tutorial on typesetting.