I can’t claim a new species, but iNat has led to a range (re-)extension for Myriopteris scabra https://www.inaturalist.org/observations/28947593 It was last reported from Yucatan in the 19th Century, isn’t in the modern floras, but in fact seems to be all over the state growing as a mortar fern.
@octobertraveler found a lichen last week that hasn’t been reported from Delaware for over a century and was thought to be extinct in the state: https://www.inaturalist.org/observations/37738046
Out on the serpentine barrens, I log a lot of Baptisia tinctoria observations when I’m wandering around because it’s a lepidopteran food plant and I like to know where it is to manage around it. I was told that the USFWS interns on a frosted elfin project found that useful this summer navigating around to check for foodplant stands. iNat works as an on-the-ground site management tool!