If the other 3 "indices" are named "_WA_Sys..." then they're auto-generated statistics that SQL Server has created on non-indexed columns.

When the AutoCreateStatistics is turned on for a database the presence of a filter on a non-indexed field (eg. "... where LastName = 'Smith' ...", where LastName is not the first field in any of the indices on that table) will result in SQL Server creating statistics on that field, looking at the selectivity of the data in that field. The definition of this is stored in sys.indexes.

Don't worry about these: they're generally good things as they help SQL Server determine better (ie. more efficient) query plans.