Oracle SQL Developer equivalent of "SELECT TOP xxx ROWS" in SQL Server
There are two parts to this.


RDBMS side
Client side (SQL*Developer)


Client Side

In SQL*Developer, you can drag+drop the table from the Connection to the worksheet in order to get a SELECT statement.  A blog on it is here.

If you use the Query Builder, you can drag+drop multiple tables and SQL*Developer will create the JOIN syntax based on defined FK.
ThatJeffSmith-Oracle goes over the speed improvements for 18.2 here.

In both cases, the Top n rows clause is not part of the resulting SQL statement.

RDBMS

Oracle database introduced a TOP n ROW clause in 12c.

Example:  https://oracle-base.com/articles/12c/row-limiting-clause-for-top-n-queries-12cr1