insert into FooBar (ID, col1, col2, col3)
values ((select max(ID)+1 from FooBar), 'a', 1, 'flort'),
       ((select max(ID)+2 from FooBar), 'b', 2, 'zap'),
       ((select max(ID)+3 from FooBar), 'c', 3, 'kazoo')

##</code><code>##

insert into FooBar (ID, col1, col2, col3)
select ID, col1, col2, col3 from (
    select max(ID)+1 from FooBar) ID, 'a' col1, 1 col2, 'flort' col3
    union
    select max(ID)+1 from FooBar), 'b', 2, 'zap'
    union
    select max(ID)+1 from FooBar), 'c', 3, 'kazoo'
)

##</code><code>##

declare
   v_ID number;
begin
   -- First table
   select max(ID) into v_ID from FooBar;
   insert into FooBar (ID, col1, col2, col3)
   values (v_ID+1, 'a', 1, 'flort');
   insert into FooBar (ID, col1, col2, col3)
   values (v_ID+2, 'b', 2, 'zap');
   insert into FooBar (ID, col1, col2, col3)
   values (v_ID+3, 'c', 3, 'kazoo');

   -- Second table
   select max(ID) into v_ID from BarBaz;
   insert into BarBaz (ID, col1)
   values (v_ID+1, 'etcetera');
end;