There are a few artist who seem to have no online presence or are inactive.
SCP-058 being the biggest example, as it comes from a Youtube video that isn't available; however it did once exist. meaning it's lost media (thats why I chose to use the image anyway, out of hope somebody might have the video.
SCP-166, By Contaiiner_ on Reddit - Unactive
SCP-169, By Ruth Taylor
SCP-239, Eddybird on Reddit - Unactive
SCP-336, vermill-iom - artist know, source not
SCP-353, Model: Lucie Hemerová, makeup design: Magda Olivová
SCP-610, Mark Powell's Dream Diorama series, (he's purposely deleted all of his online presence)
With all that being said, if I've missed any credit whatsoever. Pleas inform me about it as I feel artist are a big part of what excels the SCP fandom, (these artist can also include photographers and photoshop.)