hardpeace,
Welcome to the forums...
This question might get more responses in a different section of the forum - though I'm not sure which one... Off Topics, perhaps (it's a busy forum)... maybe Songwriting? Not sure...
Anyway... there are not a lot of "Rockers" posting songs, but that doesn't mean it isn't available in the RealTracks. There are DEFINITELY a lot of RealDrums that will work for Rock. And a lot of Bass RealTracks. You can hear sample of the RealTracks here:
https://www.pgmusic.com/realtracks.all.php?os=winCheck out the Metal tracks. And the Punk tracks. (just to name a few).
I'm mainly a Country and Singer/Songwriter type, but you can hear a few (sorta) Rock tracks on my website Song List page
http://www.floydjane.com/Songs/Player.htmlLook for these songs:
This I Love Tammy Tattoo
Tracks And Roads
1972
None Of It Matters (uses the BIAB Punk tracks)
Cuckoo
Bad Enough
They are not real "heavy" but they might give you some idea. (I don't have a Rock voice, so I don't do a lot of it)