US NOAA has a (still generally useful) list of links to various impacts:

<https://www.pmel.noaa.gov/elnino/impacts-of-el-nino>

Those include: hydrology (floods, drought), sea-surface temperatures (hotter or cooler, both of which impact local ecologies and fisheries), storms (weaker hurricane season in the Atlantic, due to high-altitude wind shear, stronger in other areas), and others: economic, fisheries, military, human health, marine life, and specific regional impacts.