You can drop multiple tables by iterating through them and executing this:
EXEC sp_MSforeachtable @command1 = "DROP TABLE ?"
However, if you try to drop a table that's being referenced by a foreign key, you'll get an error like
Msg 3726, Level 16, State 1, Line 1
Could not drop object 'dbo.Table1' because it is referenced by a FOREIGN KEY constraint.
If you just want to do it manually then simply repeat the statement a few times untill the tables with the reference are dropped (e.g. if Table2 has a reference to Table1, then at first run Table1 cannot be dropped while Table2 is dropped, and at second run Table1 can then be dropped since Table2 is no more).