I'll try to do better in 2020 ...
As it turned out, one of my Christmas presents was a book by Michael Ochs - 1000 Record Covers. Kudos the Ochs for putting this project together. He's done way more than I'll ever accomplish in this realm.
I've already spent way too much time pawing through the book. It reflects dozens of fascinating album covers (including several that I'd previously listed). That said, the funny thing is how many of the 1000 covers aren't all that impressive.
Does anyone think Joni Mitchell's "Mingus" is a stunning cover? Admittedly Mitchell designed the cover, but so what ... Similarly, what's so special about the first James Taylor LP for Apple Records?
Clearly none of us are going to agree on what constitutes a great album cover, but those differences do makes for some interesting discussions.