In our main retirement accoutns, we go 55/25/20 in to Total Stock Market, Total International Stock, Total Bond, personally.
So if I wanted to be very aggressive for me, I'd go 100% Total Stock Market. Which I do in our HSA.
If you wanted to be even more aggressive than that, you can skew towards small-cap - there is an extended market fund who's name is failing me that is basically everything except the S&P 500.
If you want to start venturing into "speculating" territory, then there are any number of sector funds you could look at. Sounds like you don't want to get so aggressive as to get into individual stock picking.