Favorite queries support shell-style parameter substitution. Save your favorite query with parameters as placeholders (e.g. $1, $2, $3, etc.):
Maybe looks like
\fs user_by_name select * from users where name = '${1:-john}'
\f user_by_name
call without args use the default value john
Maybe looks like
\f user_by_namecall without args use the default value john