recent killer!sans drawing is by Undriel on DeviantArt (link: https://www.deviantart.com/undriel/art/Killer-Sans-829136540)

blueberry sans drawing was made by shirochiidesu on Tumblr (link: https://shirochiidesu.tumblr.com/post/145234737636/eyyyyyy-feels-post-do-not-kill-the-blueberry-you)

nightmare!sans drawing is by resetale on DeviantArt (link: https://www.deviantart.com/resetale/art/Commission-Work-Nightmare-Sans-811607780)

ink!sans drawing is by clairdelune on DeviantArt (link: https://www.deviantart.com/clairdelune86/art/Ink-Sans-665654918)

geno!sans drawing is by Mmad-sm on DeviantArt (link: https://www.deviantart.com/mmad-sm/art/Aftertale-AU-696361227)

older killer!sans drawing is by MakiBlog on Twitter (link: https://twitter.com/MakiblogN/status/1118306278151995394)

and the glitchtale art is, of course, by Camila Cuevas (link: https://youtu.be/BuwUgUfZFXk)

the artist who drew echo!sans is not found but it was reposted on Pinterest on this link: https://www.pinterest.com/pin/667517975990495474/
which still means that it was also reposted, the artist who drew sour!sans was also not found but its seen in several amino posts

again, please do not harrass the art thief. just ask them to take down the art and report them.