Honestly, my favorite tool is just a cheapo chef's knife from Ikea or somewhere like that. I occasionally sharpen it with a slab of iron and use it for like 90% of all cutting I do.

Then there are a few robots I use: a kitchen assistant with a dough hook that makes all my bread with zero hassle (it also has two more accessories that can be used for example for flax seed mayonnaise), a "multi-cooker" (like a crock pot and a rice cooker in one) that I mostly use to make rice (and if I went back in time, I'd just buy a simple cheap rice cooker instead, but oh well) and, undoubtedly, my cheapo drip coffee maker. I hate brands so I just buy slightly-above-the-cheapest stuff, good enough so it doesn't break, but that's it. 90% it's good enough. I also have a cheap bamboo steamer basket that is slightly coming apart at the seams, but it's been great for a lot of things, from spring rolls to dumplings, seitan sausage and even steaming soy beans to make milk.

Oh, honorable mention to my tortilla press, though lately I've started to just use a rolling pin as that gets the tortillas thinner than with the press.