Dear @David74000,
No, the SP object is not available in Plumsail Forms as we do not load these scripts, though they can still be manually added to the form.
But the recommended way is to use the Graph API. Put this into JavaScript editor:
var ts = new GraphQueryable(graph, "termStore/groups");
ts.setEndpoint("beta");
ts.get().then(function(groups){ console.log(groups); });
For more info and a complete set of action, please, look here - https://docs.microsoft.com/en-us/graph/api/resources/termstore-store?view=graph-rest-beta