I'd be shocked to learn that the Iron Maiden cover intended to pay homage to the EWF cover. They both use Egyptian imagery but "Powerslave" isn't an obvious attempt to emulate "All 'n All"...
Best of the Lovin Spoonful (1967) and The Very Best of the Lovin Spoonful (1970) (I can't post pictures)
As the title is 'homage' rather than copy, my favourite homage is the double fold-out cover of Rush's Exit - Stage Left, which shows all the characters from their studio album covers about to go out onto the stage. (I don't know how to post pictures, so hopefully someone else will post the examples.)
Ohio Players core album covers are so thematically unified that later Westbounds are homages to earlier one and later Mercury ones are homages to earlier ones.