There are AWESOME themes in StarCraft 2!
I suggest that Blizz increase they playlist by 2-3 new themes for each race.
My suggestions for Terran are the next
https://www.youtube.com/watch?v=SAqJYQgMV5Y
Not sure if this part is ingame, i have heard the NOVA theme but i cant remember if this was the one.
https://youtu.be/UGC6XDUaaWA?t=413
And finally a classic
https://www.youtube.com/watch?v=Zs8wJ5kGcHo