How can I list Oracle editions granted?
DBA_TAB_PRIVS is what you're looking for. A demo is the best way to illustrate.

Create the edition.

SQL&gt; create edition wibble;

Edition created.

SQL&gt;


No grants yet:

SQL&gt; select table_name as edition_name, grantor, grantee
  2  from dba_tab_privs
  3  where privilege='USE'
  4  and table_name='WIBBLE';

no rows selected

SQL&gt;


Edition created, shouldn't be able to use it.

SQL&gt; conn phil/phil
Connected.
SQL&gt; alter session set edition = wibble;
ERROR:
ORA-38802: edition does not exist


Grant:

SQL&gt; conn / as sysdba
Connected.
SQL&gt; grant use on edition wibble to phil;

Grant succeeded.

SQL&gt; 


Should be able to use it now:

SQL&gt; conn phil/phil
Connected.
SQL&gt; alter session set edition=wibble;

Session altered.

SQL&gt;


Grants are now visible:

SQL&gt; select table_name as edition_name, grantor, grantee
  from dba_tab_privs
  where privilege='USE';

EDITION_NAME                   GRANTOR GRANTEE
------------------------------ ------- -------
ORA$BASE                       SYS     PUBLIC
WIBBLE                         SYS     PHIL

SQL&gt;