"Quick Characters" is a menubar app that gives you quick access to special characters that have hard-to-remember keyboard equivalents. (Examples: ©, ®, ™, €, ¥, ÷)
Simply launch the app, note the "Quick Characters" icon in the menubar (upper right of your screen), select a character and paste it into your document. Pasted characters will match whatever font you are using in your document.
(NOTE: Some fonts do NOT contain a full character set. If the appropriate character doesn't appear after pasting then select a different font in your document.) Cheers!