I work with fungi in the Pacific Northwest of the US, here are some of mine:
Danny’s DNA Discoveries, https://www.alpental.com/psms/ddd/index.htm constantly updated, heavy on sequencing
Mykoweb, California centric, https://mykoweb.com/CAF/index.html still useful for West coast, updates infrequent
MushroomExpert, https://www.mushroomexpert.com/ More of a North American focus. Note distribution.
North American Cortinarius Collections, https://nacorts.com/ a good, evolving site for Cortinarius
Mushroom Appreciation, https://www.mushroom-appreciation.com/ casual style, still technical. I enjoy the descriptions and comparisons.
Articles:
Fungal Systematics and Evolution https://fuse-journal.org/
Also see General below.
Books:
Mushrooms of Cascadia, Seigel and Schwarz
Mushrooms of Cascadia, Beug
Mushrooms of the Pacific Northwest, Trudell and Ammirati
Ascomycete Fungi of North America, Beug
Phaeocollybia of the Pacific Northwest North America, Norvell and Exeter, https://www.researchgate.net/publication/255719436_Phaeocollybia_of_Pacific_Northwest_North_America
Ramaria of the Pacific Northwest North America, Exeter, Norvell and Cazares, https://www.researchgate.net/publication/255719422_Ramaria_of_the_Pacific_Northwest
Handbook to Strategy 1 Fungal Species in the Pacific Northwest Forest Plan, Castellano et. al. https://www.fs.usda.gov/pnw/pubs/pnw_gtr476.pdf
Handbook to Additional Fungal Species of Special Concern in the Northwest Forest Plan, Castellano et. al. https://www.fs.usda.gov/r6/reo/survey-and-manage/downloads/fungi/handbook-fu-pnwgtr572-2003.pdf
Ecology and Management of Commercially Harvested Chanterelle Mushrooms, Pilz et. al. https://www.fs.usda.gov/pnw/pubs/pnw_gtr576.pdf
General:
Pubmed, https://pubmed.ncbi.nlm.nih.gov/ create an account, set up your taxa and receive notice of new papers
Stork, https://www.storkapp.me/ create an account, set up your taxa and receive notice of new papers
Academia.edu https://www.academia.edu/ create an account, set up your taxa and receive notice of new papers
The Forest Service has thousands of publications many of which are on specific taxa. Search on your taxon and see what pops up https://research.fs.usda.gov/treesearch