AR Comparison Guide: ARCore vs. ARKit vs. Vuforia vs. AR Foundation

One other cross-platform (i.e. using either ARKit or ARCore as a base) AR solution is Niantic's "Real World Platform" - https://nianticlabs.com/blog/nbrdc-update-110619/

For reference, Vuforia currently seems to be the most installed SDK on both iOS (53%) and Android (70%) apps, beating ARKit (45%) and ARCore (34%).

Source: https://appfigures.com/top-sdks/ar_vr/all