Metal Archives tags all of the nsbm bands. Outside of that you’re wading into the realm of subjectivity. You’ll have to decide where you draw the line. For example, there are plenty of bands who did/do not have fascist lyrics, but some of the members had/have shitty beliefs. And some of those people have at least partially walked back their statements, attributing them to being an edgy teen or whatever. Lots of gray area unfortunately