I agree with many that the black and red are overwhelming on many and make the book a bit less approachable. Warm tones and rich wooden boxes would be more welcome. The 8.5x11" filing cabinets just won't fly. I did like some with the drawer frames/pulls, but put a more generic idea in the frame (perhaps "Ideas"?). From the batch so far, some of my favorites are #64 TopHills, #21 & #22 BigPoints, #13, 14 D'Estudio. Unless that pull quote is from Luhmann or maybe Eco or someone internationally famous, save it for the rear cover or maybe one of the inside flaps. There's an interesting and approachable stock photo I've been sitting on that might work for your cover: Brain and ZK via https://www.theispot.com/stock/webb. Should be reasonably licensable and doesn't have a heavy history of use on the web or elsewhere.

old antiqued