Around the time of Windows 1.0, there were several competing multi-tasking windowing systems that were character based, notably DESQview [0] and TopView [1]. They got a lot of buzz at the time but never really took off.

I worked on a TopView clone (eventually released as Mondrian) for Dynamical Systems Research that had pre-emptive multitasking (years before Windows ever did) and was quite snappy on an 8086 processor running multiple apps. DSR was acquired by Microsoft for the TopView tech, but the big payoff for them was Nathan Myhrvold [2], who went on to become CTO, and David Weise, who figured out how to get Windows to run in protected mode [3], really launching Windows as a usable product (and ultimately inaugurating the split from IBM over OS/2).

[0] https://en.wikipedia.org/wiki/DESQview [1] https://en.wikipedia.org/wiki/IBM_TopView [2] https://en.wikipedia.org/wiki/Nathan_Myhrvold [3] https://www.wincustomize.com/article/63898/david-weise-the-m...