I like use a 5.5 x 8.5 or 9 x 12 Strathmore 300 Sketch tablet for notes. They are sturdy and the paper is quite good. They are a pain if you want to scan/copy them as the paper is either smaller or larger than standard letter size.
Yes I also use sketch pads with no lines (The grey spiral-bound ones sold by WHSmith in the UK). I don't understand the attraction of lines given that software is hard to describe without diagrams.
https://www.strathmoreartist.com/draw-sketch/id-300-series-s...