Vitus Park(as mentioned)
Piddy(I think that was the name, so I'd finally have a two home races! The fast-flowing turns over blind crests are even more amazing than Vitus)
Magnificient Park(the fictive story about it says it replaced Le Mans as 24 hours event, but I'd seriously drive such a race there!)
Troyton(cool track, especially with touring cars, feels as if someone put Bathurst and Monaco into a blender)
Thermalito(DDF Racer's track, he ported it to AMS and it felt great to drive during his event)
I think there are others like a different take on a Nordschleife(was that Machwerk or some other -ring track?) or something like Rattlesnake Point.
I also think S397 should update all of their fictive tracks, especially Lienz.
I'd pay for a "best of mod tracks officially supported by S397"pack with the fictional tracks above. They were just too good not to have
I have said it and i will keep saying it. Blackwood from LFS. Not only that circuit is CRAAAAAAAAAAAAZY fun to drive, but it absolutely feels realistic. There's neither insane elevation changes not 100% magically flat surface. It doesn't take a nurgburgring+ amount of size nor is it a compact 1km square multi level parking lot as a race track, and its got all the parts required to make it a fun low class race track.
As others mentioned, I read Toban Raceway from rFactor 1 and i raise you to add Mills Metro Park. Seriously underrated.
Special mention to Gran Turismo unrealistically unsafe but very pretty tracks and any classic need for speed (2, 3, hot pursuit 2) tracks.
I'd pick Tokyo Route 246 from GT4. If I had to name it in the real life, I'll name it Meiji JinguMetro Circuit given the route of the circuit sits close to Meiji Jingu area in real life. The chief problem was, the route runs around Akasaka Imperial Residence, so far as I concerned. Notable landmarks around the area includes Japan National Stadium, Meiji Jingu Stadium, Meiji Imperial Gallery (if anyone wants to search in google maps)
The latter in fact even in some way with feasibility to perform extension IRL
That said, haven't personally been on ground in reality (but drove the GTR2-conversion with joy) so don't actually know if the hills will fit the mountain layout. But cool for sure!