w3schools.com
Arrows
Arrows - HTML Unicode UTF-8 - W3Schools
General Punctuation
General Punctuation - HTML Unicode UTF-8 - W3Schools
Box Drawings
Box Drawings - HTML Unicode UTF-8 - W3Schools
Letterlike Symbols
W3Schools offers free online tutorials, references and exercises in all the major languages of the web. Covering popular subjects like HTML, CSS, JavaScript, Python, SQL, Java, and many, many more.
Block Elements
Block Elements - HTML Unicode UTF-8 - W3Schools
Currency Symbols
Currency Symbols - HTML Unicode UTF-8 - W3Schools