This is not trivial, see my answer here
I’ve stumbled upon a node which actually makes this possible in blueprints though, Tags filtering is just not present in the default ARFilter node.
Here is a prototype implementation that will recursively fetch child blueprint classes until it doesn’t find any new ones anymore.
Just note the input parameter is by-ref. Other variables are locals.
Usage is a bit tedious, you need to pass in a full string reference like so :
Also note that it won’t fetch native classes, those are not assets. I’m not aware of any blueprint way to find native subclasses. C++ is much more fit for this.