As far as i know, the minimal required permission set solution in this case is to create a store procedure thats executed within an impersonated context. Do this by:
create procedure [schema].[get_idx_info] with execute as [user with view database state perms and select perms or OWNER] as begin select db_name() as DBName, object_schema_name(i.object_id) as SchemaName, object_name(i.object_id) as TableName, isnull(i.name,'(HEAP)') as IndexName, ps.SizeInPages from sys.indexes i inner join ( select ps.object_id,ps.index_id,sum(ps.row_count) as IndexRows, sum(ps.used_page_count) as SizeInPages, count(*) as PartitionCount from sys.dm_db_partition_stats ps group by ps.object_id,ps.index_id ) ps on ps.object_id = i.object_id and ps.index_id = i.index_id where object_schema_name(i.object_id) not in ('cdc','sys') end see: (https://learn.microsoft.com/en-us/sql/t-sql/statements/execute-as-clause-transact-sql)
Then grant users execute on that stored procedure. This will allow the user to view that info w/o additional permissions (aside from EXECUTE on the SP).
to test:
create login [nonprivileged] with password = 'eqreADf$a23asd'; go create user [nonprivileged]; go grant execute on [schema].[get_idx_info] to [nonprivileged]; go execute as user = 'nonprivileged'; /* should work */ exec [schema].[get_idx_info]; revert; execute as user = 'nonprivileged'; /* should fail */ select * from sys.dm_db_partition_stats revert; execute as user = 'nonprivileged'; /* should fail */ select * from sys.indexes; revert; drop user [nonprivileged]; go drop login [nonprivileged]; go By doing this, the stored procedure will execute with the permissions of either the designated user or (if set to OWNER) the creator/owner of the stored procedure, instead of the permissions of the user calling EXECUTE (this is default behavior, which is why sys.indexes is filtering by select permissions in your case).