Where are Notepad, 7-Zip and Snipping Tool on a Mac?

Notepad. TextEdit, in Applications, opens as a rich-text editor by default, which is why it looks like WordPad. Its settings (⌘,) → New Document → Plain text turn it into Notepad, and turning off smart quotes there stops it replacing straight quotes in code. CotEditor, free, is the Notepad++ of the Mac: tabs, syntax colouring, find and replace with regular expressions.

7-Zip. macOS makes and opens zip files itself: right-click a file or folder → Compress, and double-click a zip to extract it next to itself. For .7z, .rar and split archives, Keka or The Unarchiver, both free, register themselves for those types so double-click keeps working.

Snipping Tool. ⌘⇧5 opens the screenshot toolbar with area, window, whole screen and screen recording; ⌘⇧4 goes straight to area selection. Marking up a screenshot: click the thumbnail that appears at the bottom right, or open the file in Preview and use the Markup toolbar.

Calculator, Sticky Notes, Character Map. Calculator and Stickies have the same names. Character Map is the Character Viewer: ⌃⌘Space, which also holds the emoji.