Some of my low carb baking endeavours from early on are listed here:
https://www.diabetes.co.uk/forum/threads/low-carb-recipes.4871/page-48#post-987609
I actually prefer the cheaper ground almonds to the finer textured almond flour/meal... I also use hazelnut, walnut and pecan flour/meal, and generally use hazelnut if I want something chocolatey.

I've also used sesame flour for low carb savoury bakes, and milled linseed and various nuts and seeds as extra ingredients for savoury stuff. I rarely use coconut flour as although it's nice and fine I found it difficult to manage as it very definitely has it's own ideas about quantities of eggs and liquids!
For sweetening, erythritol and stevia, separately or in combination, are considered to be safe for diabetic use, and since their carb content is not digestible they shouldn't raise glucose levels.
I think the main weirdo ingredient that you find in some low carb baking recipes (particularly Diet Doctor) is psyllium husk which I believe is used as a binding agent, but it's also used as a laxative! However, AFAIK it's
not essential.