'Non-cutlery' knives - there's no such thing, Tefal. Knives are classed as cutlery. But I assume you mean 'knives not designed for eating food'?
If you mean vaguely 'tactical' knives, then those are oftentimes great fun to use to cook and eat with, as well as mess about outside with in the garden, trimming whatever needs (or doesn't!) trimming. I use a variety whenever I'm around the place, my favourites being my Shirogorov Hati and Rockstead Shin, along with things like Sebenzas and Umnumzaans if you want to see the extent to which pocket knives can combine beauty (subjective, of course) and extraordinary skill in manufacturing in terms of tolerances and materials used. The pleasure is not just in the using (though the Shin has been rubbish in my use, but the Hati exceptional), but also in the appreciation of what goes into making them. But not everyone will appreciate those things. Some people just want something that's cheap and cuts (relatively) well.
Regarding your desire for a razor blade - that's going to be iffy as carrying a razor blade around may well be seen as a no-no. There are people who take a razor or scalpel blade, and create a folding kydex handle which means the blade can be safely folded (ticking the 'non-locking' criteria) and also making the thing more useable than a raw blade. If you're interested, I'll have a dig on the forums I'm on and link to the makers of these types of things. There may well be production versions out there too, I'm just not aware of them (I like buying things made here by similar folk, rather than importing from factories in lands afar).