I've recently tried Midori/Md b6 slim and really love the size - seems to be just perfect for me: compact enough for edc (the regular TN/a5 slim size was slightly too big)
Midori MD B6 Slim Grid Notebook, £13.20
MD Paper Notebook Diary 2023 - B6 Slim • Miso Paper UK
Midori MD Notebook Light B6 Slim
Midori MD B6 Slim Lined Notebook, £13.20
Midori notebook cover, goat leather, B6 slim
Midori MD B6 Slim Blank Notebook 88 Sheets 265gsm Medium | Cass Art
MD Paper B6 Slim Notebook, Lined Paper • Miso Paper UK