Teaching in the Metaverse: Chapter 5.5. Other apps.

A quick google search will turn up tons of standalone apps. Many of them are designed for a specific learning level or a specific set of topics.

They can often be found on the major VR storefronts like Steam, The Quest store, Viveport, etc. The more you search and browse the more you will discover and perhaps find some other options that might be useful to you. Some will be free, others will be paid. Some will be focused on standalone headsets and others will require PCVR, so you kind of have to just spend some time sleuthing around.