When I type '#' vscode suggests "#pragma region" and "#pragma endregion". I never use those snippets and the suggestions can be quite annoying especially if I intend to navigate using arrow keys after typing '#'. I figured out that the suggestions come from snippets in the built-in extension "C/C++ Language Basics". Disabling that extension is not an option because syntax highlighting goes away with it.
Individual snippets may be disabled by opening the command palette (ctrl+shift+p), typing "insert snippet", pressing enter, and clicking with the mouse on the pictogram of an eye with a line over it thus removing the line.
I don't know how to do the last part without a mouse. If you know please comment.