Here is a short list off the top of my head.

Simon and Garfunkel Book Ends Original pressing.

Led Zeppelin Houses of the Holy later U.S. pressing with GP written in the dead
wax.

Donovan A gift from a flower to a Garden. Original Epic stereo

Genesis Tresspass. Japanese pressing

Grateful Dead American Beauty original US pressing

These are just a few that are easy to find for the most part.

As for audiophile reissues I would say that MFSL is hit and miss and tend to be
way over priced. Classics are mostly excellent but they have a few turkies as
well. And DCC when you can find them are consistantly excellent. Speakers
Corner reissues are also excellent. EMI Century reissues are usually good and
the EMI millenium reissues are usually bad. Simply Vinyl varies widely from
title to title.

Then ther is classical and Jazz and other genres. Books have been written on
the subject.