The System table system.numbers_mt is the same as the System table system.numbers, but its reading is parallelized, and numbers can be returned in any order. Suitable for generating test data or performing data filling.
Example
Query data:

SELECT * FROM system.numbers_mt LIMIT 10;

Query results:

┌─number─┐ 
│      0 │ 
│      1 │ 
│      2 │ 
│      3 │ 
│      4 │ 
│      5 │ 
│      6 │ 
│      7 │ 
│      8 │ 
│      9 │ 
└────────┘