Which special characters to accept email id ?

Email addresses cannot contain '<' or '>' characters at any time: Email address - Wikipedia, the free encyclopedia[^]
Even then, the rules are different for the Local and Domain parts of the address "local@domain"
It clearly says that the domain part can only contain:

uppercase and lowercase Latin letters A to Z and a to z;
digits 0 to 9, provided that top-level domain names are not all-numeric;
hyphen -, provided that it is not the first or last character.

No other special characters are valid.
The local part is more flexible:

uppercase and lowercase Latin letters A to Z and a to z;
digits 0 to 9;
special characters !#$%&'*+-/=?^_`{|}~;
dot ., provided that it is not the first or last character unless quoted, and provided also that it does not appear consecutively unless quoted (e.g. John..Doe@example.com is not allowed but "John..Doe"@example.com is allowed);
space and "(),:;<>@[\] characters are allowed with restrictions (they are only allowed inside a quoted string, as described in the paragraph below, and in addition, a backslash or double-quote must be preceded by a backslash);
comments are allowed with parentheses at either end of the local-part; e.g. john.smith(comment)@example.com and (comment)john.smith@example.com are both equivalent to john.smith@example.com.

If you are talking about the message body, then generally speaking '<' and '>' will delimit HTML formatting data which is normally permitted - but any other use of such characters must replace them with &lt; and &gt; respectively in order to show them as < and > when the user reads the mail.