The core "uber-snippets" for sure should be covered I suppose:
[*] Ditto (with working filtering on Tags example since this seems to be the major recurring problem)
[*] Jot
[*] Wayfinder (with URL reference to example implementations)
[*] eForm (current documentation is really great actually)
Ryan Thrash, MODX Co-Founder
Follow me on Twitter at @rthrash or catch my occasional unofficial thoughts at thrash.me