The list of my favourite gadgets has changed a lot over the decades, depending on lifestyle and capability.
I have tried and hated stick blenders because they make a mess. The stuff being chopped flies up from the goblet and goes all over the place. What I like is my 22yo Braun food processor. It has two goblets -- one large and one small -- and does a lot of stuff I want.
Then I like my grater. There are actually several interchangeable ones that come fitting on top of a container, so that what you are grating falls through into the container.
I have quite a collection of hand whisks, but for small amounts such as a single egg,
this one is ideal.
Although I like ovens for cooking, I also find a microwave an unglamorous essential for a whole range of tasks.
And then I love my stainless steel lidded pans. They go on the stove or in the oven and can be used for most things. And they are a breeze to clean if you use a bit of vinegar.