If you extend to include artists, there's also the gravestone for Patrick Caulfield in Highgate which comprises the 4 large stylised letters D E A D "pierced through a sleek slab of stone, a stark statement of fact"[0].

[0] https://highgatecemetery.org/visit/cemetery/east

A non-Modernist example:

Mimar Sinan, the preeminent architect of peak Ottoman Empire, is buried in a tomb of his own design.

Sinan died in AH 996 (1587-88 CE) and is buried in a tomb in Istanbul, a türbe of his own design, just to the north of the Süleymaniye Mosque, across a street named Mimar Sinan Caddesi in his honour. He was buried near the tombs of his greatest patrons: Sultan Süleyman I and Sultana Haseki Hürrem, Suleiman's wife. Above the iron-grilled prayer window of his tomb is an epitaph written in Ottoman Turkish by the poet Mustafa Sai. It gives the year of his death and records that Sinan built 400 masjids (small mosques), 80 Friday mosques and the Kanuni Sultan Suleiman bridge at Büyükçekmece.

https://en.wikipedia.org/wiki/Mimar_Sinan#Death_and_Legacy

https://en.wikipedia.org/wiki/File:Mimar_Sinan5.jpg

> It may seem strange to begin the list of architects with one who is not generally considered an American architect.

The audacity of some people!

Wouldn’t it be cool if an architect made an entire house into their grave? Imagine if they buy some plot of land, get buried there when they die and arrange to have a home built right on top with their grave site being at the center of the home, where they are commemorated by some statue or something. And sometimes when the sunlight hits just right it will be like you can still feel their presence in this home they designed.

You could say that the famous ones, their hallmark buildings are how we remember them, these are the markers of their achievement. The headstones are just a formality.

The title calls for a Wikidata query: https://w.wiki/xhh

A good architect learns to keep things simple.

Where is Howard Roark's grave?