.Any character\dDigit [0-9]\DNon-digit\wWord char [a-zA-Z0-9_]\WNon-word\sWhitespace\SNon-whitespace^Start of string$End of string\bWord boundary*0 or more+1 or more?0 or 1{n}Exactly n{n,m}Between n and m[abc]Character class[^abc]Negated class(...)Capture group(?:...)Non-capturing(?=...)Positive lookahead(?!...)Negative lookahead|Alternation