Without statistics, indexes on SQL tables are nearly useless, but that's no excuse to have a bunch of duplicates sitting around. These two views work in tandem with one-another, the first view vStatisticsWithColumns returns each of the statistics in your database with the names of the first 25 columns it covers. The second view vDuplicateStatistics returns the names of the statistics that cover the same columns. This does not indicate that the statistic is 100% duplicated, as the stat may have more than 25 columns - but I'll leave that part up to you.

See also: Finding Duplicate SQL Indexes.

CREATE VIEW vStatisticsWithColumns AS
SELECT
	tbl.[name] AS TableName,
	idx.[name] AS IndexName,
	INDEX_COL( tbl.[name], idx.indid, 1 ) AS col1,
	INDEX_COL( tbl.[name], idx.indid, 2 ) AS col2,
	INDEX_COL( tbl.[name], idx.indid, 3 ) AS col3,
	INDEX_COL( tbl.[name], idx.indid, 4 ) AS col4,
	INDEX_COL( tbl.[name], idx.indid, 5 ) AS col5,
	INDEX_COL( tbl.[name], idx.indid, 6 ) AS col6,
	INDEX_COL( tbl.[name], idx.indid, 7 ) AS col7,
	INDEX_COL( tbl.[name], idx.indid, 8 ) AS col8,
	INDEX_COL( tbl.[name], idx.indid, 9 ) AS col9,
	INDEX_COL( tbl.[name], idx.indid, 10 ) AS col10,
	INDEX_COL( tbl.[name], idx.indid, 11 ) AS col11,
	INDEX_COL( tbl.[name], idx.indid, 12 ) AS col12,
	INDEX_COL( tbl.[name], idx.indid, 13 ) AS col13,
	INDEX_COL( tbl.[name], idx.indid, 14 ) AS col14,
	INDEX_COL( tbl.[name], idx.indid, 15 ) AS col15,
	INDEX_COL( tbl.[name], idx.indid, 16 ) AS col16,
	INDEX_COL( tbl.[name], idx.indid, 17 ) AS col17,
	INDEX_COL( tbl.[name], idx.indid, 18 ) AS col18,
	INDEX_COL( tbl.[name], idx.indid, 19 ) AS col19,
	INDEX_COL( tbl.[name], idx.indid, 20 ) AS col20,
	INDEX_COL( tbl.[name], idx.indid, 21 ) AS col21,
	INDEX_COL( tbl.[name], idx.indid, 22 ) AS col22,
	INDEX_COL( tbl.[name], idx.indid, 23 ) AS col23,
	INDEX_COL( tbl.[name], idx.indid, 24 ) AS col24,
	INDEX_COL( tbl.[name], idx.indid, 25 ) AS col25,
	dpages,
	used,
	rowcnt
FROM
	sysindexes idx
INNER JOIN sys.objects tbl
	ON idx.[id] = tbl.object_id
WHERE
	tbl.is_ms_shipped = 0
	AND indid > 0 
	AND INDEXPROPERTY(tbl.object_id, idx.[name], 'IsStatistics') = 1
GO

CREATE VIEW vDuplicateStatistics AS
SELECT
	l1.TableName, 
	l1.IndexName, 
	l2.IndexName AS DuplicateIndex, 
	l1.col1, 
	l1.col2, 
	l1.col3, 
	l1.col4, 
	l1.col5, 
	l1.dpages,
	l1.used,
	l1.rowcnt
FROM
	vStatisticsWithColumns l1 
INNER JOIN vStatisticsWithColumns l2
	ON l1.TableName = l2.TableName
	AND l1.IndexName <> l2.IndexName
	AND l1.col1 = l2.col1
	AND COALESCE(l1.col2,'') = COALESCE(l2.col2,'')
	AND COALESCE(l1.col3,'') = COALESCE(l2.col3,'')
	AND COALESCE(l1.col4,'') = COALESCE(l2.col4,'')
	AND COALESCE(l1.col5,'') = COALESCE(l2.col5,'')
	AND COALESCE(l1.col6,'') = COALESCE(l2.col6,'')
	AND COALESCE(l1.col7,'') = COALESCE(l2.col7,'')
	AND COALESCE(l1.col8,'') = COALESCE(l2.col8,'')
	AND COALESCE(l1.col9,'') = COALESCE(l2.col9,'')
	AND COALESCE(l1.col10,'') = COALESCE(l2.col10,'')
	AND COALESCE(l1.col11,'') = COALESCE(l2.col11,'')
	AND COALESCE(l1.col12,'') = COALESCE(l2.col12,'')
	AND COALESCE(l1.col13,'') = COALESCE(l2.col13,'')
	AND COALESCE(l1.col14,'') = COALESCE(l2.col14,'')
	AND COALESCE(l1.col15,'') = COALESCE(l2.col15,'')
	AND COALESCE(l1.col16,'') = COALESCE(l2.col16,'')
	AND COALESCE(l1.col17,'') = COALESCE(l2.col17,'')
	AND COALESCE(l1.col18,'') = COALESCE(l2.col18,'')
	AND COALESCE(l1.col19,'') = COALESCE(l2.col19,'')
	AND COALESCE(l1.col20,'') = COALESCE(l2.col20,'')
	AND COALESCE(l1.col21,'') = COALESCE(l2.col21,'')
	AND COALESCE(l1.col22,'') = COALESCE(l2.col22,'')
	AND COALESCE(l1.col23,'') = COALESCE(l2.col23,'')
	AND COALESCE(l1.col24,'') = COALESCE(l2.col24,'')
	AND COALESCE(l1.col25,'') = COALESCE(l2.col25,'')