See I don't understand why fentek and SP both offer all of these novelty keys and don't offer double shot "WASD" sets as well.
The problem is this, there is no consistent profile between manufacturers, and even different models. So a generic keycap set could be made, but then when everyone tries to install them on their specific keyboard it might be correct, close, or completely wrong (most likely just close). The Esc key is separated from the other keys by enough space that "being close" is usually good enough, not a spec that most people would want to deal with when it comes to the primary typing keys on their keyboard. This is why you typically only see WASD sets being offered by certain manufacturers spec'd for their product only.
This was one of the beautiful design characteristics built into the Model M, just one profile regardless of row.