Susceptibility weighted imaging and maximum intensity projections are not currently supported in BIDS, but there is an extension proposal that adds both. It's called BEP004 (https://docs.google.com/document/d/1kyw9mGgacNqeMbp4xZet3RnDhcMmf4_BmRgKaOkO2Sc
). It's not under active development, unfortunately, but I think it's also pretty mature. I would recommend using the proposed suffixes, entities, metadata, etc. from that BEP. It won't be BIDS compatible, and you'll want to include the files in your bidsignore file, but it should be much closer to BIDS than anything else.
I think there's an angio suffix in BIDS that you can use for your TOF data.
I hope that's helpful.