How to retrieve tablespace default storage Parameters?

SELECT TABLESPACE_NAME "TABLESPACE",
INITIAL_EXTENT "INITIAL_EXT",
NEXT_EXTENT "NEXT_EXT",
MIN_EXTENTS "MIN_EXT",
MAX_EXTENTS "MAX_EXT",
PCT_INCREASE
FROM DBA_TABLESPACES;

TABLESPACE INITIAL_EXT NEXT_EXT MIN_EXT MAX_EXT PCT_INCREASE
---------- ----------- -------- ------- ------- ------------
RBS 1048576 1048576 2 40 0
SYSTEM 106496 106496 1 99 1
TEMP 106496 106496 1 99 0
TESTTBS 57344 16384 2 10 1
USERS 57344 57344 1 99 1

How to retrieve information tablesapce and associated datafile?

SELECT FILE_NAME, BLOCKS, TABLESPACE_NAME
FROM DBA_DATA_FILES;

FILE_NAME BLOCKS TABLESPACE_NAME
------------ ---------- -------------------
/U02/ORACLE/IDDB3/RBS01.DBF 1536 RBS
/U02/ORACLE/IDDB3/SYSTEM01.DBF 6586 SYSTEM
/U02/ORACLE/IDDB3/TEMP01.DBF 6400 TEMP
/U02/ORACLE/IDDB3/TESTTBS01.DBF 6400 TESTTBS
/U02/ORACLE/IDDB3/USERS01.DBF 384 USERS

How to retrive Statistics for Free Space (Extents) of Each Tablespace?

SELECT TABLESPACE_NAME "TABLESPACE", FILE_ID,
COUNT(*) "PIECES",
MAX(blocks) "MAXIMUM",
MIN(blocks) "MINIMUM",
AVG(blocks) "AVERAGE",
SUM(blocks) "TOTAL"
FROM DBA_FREE_SPACE
GROUP BY TABLESPACE_NAME, FILE_ID;

TABLESPACE FILE_ID PIECES MAXIMUM MINIMUM AVERAGE TOTAL
---------- ------- ------ ------- ------- ------- ------
RBS 2 1 955 955 955 955
SYSTEM 1 1 119 119 119 119
TEMP 4 1 6399 6399 6399 6399
TESTTBS 5 5 6364 3 1278 6390
USERS 3 1 363 363 363 363

PIECES shows the number of free space extents in the tablespace file, MAXIMUM and MINIMUM show the largest and smallest contiguous area of space in database blocks, AVERAGE shows the average size in blocks of a free space extent, and TOTAL shows the amount of free space in each tablespace file in blocks. This query is useful when you are going to create a new object or you know that a segment is about to extend, and you want to make sure that there is enough space in the containing tablespace.