Some Unicode symbols used to represent the Enter ↵ key on keyboards:
I took a quick survey of keyboards to see what graphics symbol they use, or none.
All Microsoft keyboards uses ↵ a thin turned arrow with a sharp 90° corner. This is the most popular graphic symbol used. If a keyboard use a return arrow symbol, it's usually with sharp 90° corner like this. Microsoft has a long horizontal line, but others may not. Some uses a big filled arrow-head.
Examples of keyboards using return arrow with sharp corner:
The ⏎ RETURN SYMBOL, with outline graphics, is used on some, but relatively rare. Including μTRON Keyboard.
↩ LEFTWARDS ARROW WITH HOOK
Apple Keyboards use this. Apple Keyboards usually do not have a glyph for the Enter key. But for European versions, they do. On euro versions, keys such as {home/end, page up/down, return/enter, delete, tab, shift}, are all using a graphic symbol, and no text. 〔☛ Apple Keyboard Gallery〕