Hello I was wondering if you know of any up-to-date resources for identifying fascist symbols. I saw a flag being displayed on my commute to work and I suspect it may be a white nationalist flag but typing a description into Google got me nowhere. It was an American flag but in the center there was a white circle around a red cross (not a Christian crucifix, more like the iron cross)

The Anti-Defamation League has a good database of hate symbols used in the US: https://www.adl.org/hate-symbols

It sounds like the symbol you saw might be something like this? 

Which is a Templar cross, used mainly by far-Right islamophobic Christian groups when it is in red on white like that.
Similar crosses and designs are used in many countries and by many groups though, so context is important:
https://en.wikipedia.org/wiki/Cross_patt%C3%A9e