See, you called it “asynchronous serial protocol” there. But one can certainly think of asynchronous serial protocols that are outside those bounds.
The Wikipedia article [0] calls this category “asynchronous start-stop signaling” but has no source.
I guess the best term is “UART protocol”, despite the limited size of the “universe”, since it’s really just a de facto convention established by decades of chips called “UARTs”.
UARTs are called universal because they can be configured to work with "any" asynchronous serial protocol (within their bounds), which usually means
- 1 start bit
- 5-9 data bits
- even or odd parity
- 1-2 or sometimes 3 stop bits
per frame. Hardware UARTs also typically oversample 16x, which is why simple software UARTs are often somewhat glitchy.