All of them. Mainly Tahiti Road, Red Rock Valley, the old Rome which was infinitely more epic than the new one, the old look of SSR5 which was also infinitely more epic than the new one, Complex String, SSR11 (if they keep the old look and don't do to it what they did to SSR5), Apricot Hill, Rome Night, Seattle, El Capitan, and Grindelwald (wow, that's a lot).
In all honesty GT5 has fairly poor course selection... GT2 may have had fewer base environments but even that seems like it would probably be better, mainly because the course menu wasn't cluttered up by a million "reverse", "time change", and "weather change" courses which could be just as easily handled by one course each and an options menu. Also, GT4 was by far the winner when it comes to base environments.