Whoa, what a difficult question, but I’ll try it.
• Macau in R3E, because this track is just crazy. Not really fun racing there, but it’s just nonsense that this circuit even exists.
• Portland in Automobilista/GSCE by Patrick Giranthon. I have a passion for this track since good old Indycar Racing days and Patricks version is the best modern one we have available.
• VIR in Assetto Corsa. Just a fantastic mod for this great track! Well done!
• Le Mans in Iracing because they just scanned the whole damn thing! Chapeau!
• Toban and Mills Metro Park in rfactor 2. Two nice examples of well made fantasy tracks
• Lake Louise in Assetto Corsa. Though not being topnotch graphic-wise this track is nevertheless stunning, especially in VR
There are so many more I could mention, however I try to keep it short.