I usually can tell if something's the Tumblr sort of art when they use warm colours, lots of yellow (for a BG for instance), textured to look like a traditional drawing or painting. They're all just copying each other instead of just taking notes and tweaking their styles. If you were to show me these images without saying who they're from, I'd most likely think they're from the same person unless they do that thing when they grossly exaggerate the ears and eyes.
From an earlier posts.
Can't find an image to show what's in my mind but imagine these but amplified. They have the same eyes but have elephant ears too.
And as for the semi-realistic, there's something very off and ugly about how they draw faces. Sometimes, it's because they can't draw lips without looking like Steven's Universe characters. But some just look off in ways I can't exactly describe.