based on your description of "aggressive' characters, you will probably like juggernauts. Assassins are a decent choice as well, constantly on the lookout for a make-or-break play
overall though, what champions can play aggressive really varies by your personal preference for it. As others have mentioned, try to save up blue essence for champions that you like after trying them out on the free rotation
Since you like
, there are quite a few champions that can pull off large-area burst damage, but not many that can match her flair
Try
and
, though swain might be a bit much to pick up out of the blue
#RULE OF THUMB: TRY THINGS OUT BEFORE BUYING THEM UNLESS YOU CAN'T HELP YOURSELF AND IF THAT'S THE CASE, TRY TO GO WITH CHEAPER CHAMPIONS