How to use wasted corner counter space?

I keep my mixer in the corner since it takes up so much room.

I keep my mixer in the corner as well because that is where it fits and takes up less room than if I had it in another area of the counter. And like you, I have a coffeepot, a toaster, paper towel rack, butter dish, canister full of utensils I use frequently, and dog food container on the counter! Not much cabinet space either. I did mount some hooks under the cabinets for coffee cups to clear out one cabinet, downsized some items I really didn't use to open up some cabinet space, cleaned up my spice/baking cabinet using bins, and small shelves so things to go above and below the shelves. You could build an appliance garage for that corner and hide your mixer, toaster, etc. until you are using it.

Get a bread box, it provides extra storage and looks nice too! I have this one and I love it: https://amzn.to/2Xasklj

You could put a corner shelf and use for spices or items that you use often.

Corners are great for tucking away some of the larger appliances. Also, maybe you can get some of the items up off the counter and onto the backsplash area. I also use a large lazy susan in one corner and have a couple of appliance on it and rotate to use the one needed. Think your organization through and place like items together or place items you use and store near where they are used most often. It's a process each individual needs to work through to make their kitchen function best for them.

Can always used those shelf systems in the corner that spin like a lazy susan, I've seen them in mostly 2 shelves, they fit in the corner cabinet.

I'm building an appliance garage in my corner to hold mixer, blender, food processor and juicer.