In addition to Zwift in a sibling post, there's TheRivet[0] that interfaces with a smart trainer and a phone mounted on the stem to do steering onscreen. TheRivet actually developed the steering concept a few months ahead of Zwift [1][2]

[0] https://getontherivet.com/ [1] https://www.dcrainmaker.com/2019/07/rivet-zwift-potential-co... [2] https://zwiftinsider.com/setting-up-your-bike-and-phone-for-...