Masked version of human HG19 reference, for removing human contaminant reads:
https://drive.google.com/open?id=0B3llHR93L14wd0pSSnFULUlhcUk

Ribosomal kmers, for ribosomal (16S/18S/etc) read removal via BBDuk:
https://drive.google.com/open?id=0B3llHR93L14wS2NqRXpXakhFaEk

