In the same way that cantrips and other spells come with an "At Higher Levels" mechanic. The race should to.
For example, a race like Dragon can be able to fly at higher level. Such as shedding skin like a snake and emerging in a new form with wings (such as eaglelike or batlike). An Ardling-Aasimar might gain permanent flight at higher levels.
An Elf might swap its (choice of) lower level spells for a higher one instead.
A Dwarf might be able to phase thru earth at-will at higher levels.
I also want to see the background with stuff to do at higher levels. But in this case, I am looking specifically at levels 9 to 12, when acquiring a fortress, magic school, sacred community, thieves guild, even starting a business, or so on.