Barleywine
Great input, everyone! Some of it reinforces my own impressions, some of it is new to me since most of my current library is much older. I see at least three or four that I'll be looking for so far.
Not specifically tarot, but always within easy reach _The Penguin Dictionary of Symbols_ Chevalier & Gheerbrant.
A book I'd wanted to read for years but had been out of print, recently reissued for kindle _Pictures from the Heart: A Tarot Dictionary_ Sandra A Thomson.
Also, reached-for more often than I might have expected _Tarot Reversals_ Mary Greer.
Well worth a read -
_The Magical World of the Tarot: Fourfold Mirror of the Universe_ Gareth Knight
and
_Marseille Tarot_ Camelia Elias
But there is an ebook I turn to when I'm having one of those early morning, haven't had my coffee moments when my brain is refusing to cooperate: Ricklef's "Pithy Tarot:"
https://jamesricklef.wordpress.com/products/pithy-tarot-ebook/
It's mostly just a bunch of quotes cobbled together for each card, but sometimes it's just what I need to shake the cobwebs loose.
two by Echol, Mueller, & Thomson are the only RWS books I still keep at hand.
Spiritual Tarot and The Heart of the Tarot
I've had many dozens make their way across my desk though and retained bits and pieces of them all.
I've only been working with the Thoth for about two years so close at hand I have
Understanding Aleister Crowley's Thoth, DuQuette. If I do another full immersion study I'll certainly get the rest of his books
Thoth Companion by Snuffin
Keywords for the Crowley Tarot by Banzhaf and Theler
I only have 3 tarot books, two are deck specific books for the Crows Magick and the Cosmic, my general book is the tarot bible by Sarah Bartlett, and I find it handy to look up the keywords for cards I'm having difficulty with though I hardly ever use it anymore.