That’d be VisiCalc from all the way back in 1979. The slam-dunk argument against Steve Jobs wanting the Apple II to be a glorified appliance with only built-in applications. A lesson he still hadn’t fucking learned by the time the iPhone came out.
Lotus 1-2-3 was the IBM PC answer to that 8-bit microcomputer program. VisiCalc had a DOS version, but it was a deliberately identical port. Bugs and all. Lotus bought the company within two years of launching its properly modern competitor.