Credits for fanart or thumbnails used:
SCP-801, and SCP-818, SCP-850, and 889, By SCP orientation on YouTube.
SCP-811, From antipuff on Tumblr. (DEACTIVATED)
SCP-828, By harvestlocks on Tumblr.
SCP-830, By SCP ILLUSTRATED.
SCP-834, By themorbidmemories on DeviantArt.
SCP-835, By HusoHuso (I know the artist name, but the site they posted the art on, seems inactive).
SCP-845, By u/iloveseacreatures on Reddit.
SCP-847, By u/chernik_moon.
SCP-871 (Thumbnail), From u/Canada3108 on Reddit.
SCP-879, By SunnyClockwork on DeviantArt.
SCP-897, SCP-898 (and additional SCP-878 art) By Daily SCP Art on Tumblr.
The rest are either random images I found on google. or ones that derive from the articles they represent.