The whole book. "Nobody remembers the singer. The song remains."
Possibly a shout-out to The Bard's Song (In The Forest) by Blind Guardian whose lyrics include the line "No-one will ever know our names, but the bards' songs will remain".
The illustration of Death cheerfully petting a confused (but not scared)-looking cat.
Death reaffirming his stance against cruelty to cats, letting one out of the box it was in during the discussion of the Schrodinger's Cat paradox.
The illustration of a kitten batting at the Death of Rats's tail. It doesn't seem to mind.
Rincewind being so moved by the sight from the moon that even he, of all people, can't manage sarcasm.
Cohen and his band went back to Fingers Madza, the Thief Who Stole Fire, and not only paid their respects, but cut him loose and gave him a sword to enact revenge against the eagle who has been eating his (regenerating) liver for a very long time.
Informed by Nuggan of how many excellent foods his worshipers are forbidden to eat, Offler the Crocodile God can't help but feel a pang of sympathy for the Nugganites. As minor as this seems, anyone who's read Small Gods will know that it's actually quite remarkable for any Discworld god to empathize with mortals: most are Jerkass Gods at best, if not downright sociopaths. But any god as ugly as Offler has got to have learned to see a mortal's point of view, to have retained followers for so long.