Comment by kees99

"Modern" tiny ISA would probably be LPC [0] which is a relatively simple encapsulation/serialization format for ISA that preserve full software compatibility, and can transport ISA signals over as few as 8 pins.

This thing was quite ubiquitous for inter-connecting some low-speed things within PC motherboards in the early 2000s. Although physically separate LPC cards did exits, those were rare and connector/pinout was never standardized.

[0] https://en.wikipedia.org/wiki/Low_Pin_Count_bus