I’d add hide and unhide into the mix. It’s not exactly a modeling tool, but it often helps when you have some tricky bits that are hard to get to. And the “F” key to make a face or an edge from selected vertices.
You are using about 1% of Blender’s features, and that’s OK. Most of the additional features were added because, in certain situations, they might speed up somebody’s workflow. Quite frankly, some of the bells and whistles were simply added because other 3D modeling software had the feature, and Blender devs didn’t want to lose face. (Don’t tell them I said so, because they are sure to come back with “But you simply can’t do x operation without y feature!!!” which is true, but if you don’t do x operation, what’s the point?)
The real trick in learning complex software like Blender is discovering what you can safely ignore. If you can model the things you want to model with the tools you know, you’re golden. Every now and then, take a look at some tool specific tutorial to see what it does and how it works, and think whether you need it in your tool box.
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