Rabbits should be able to “leap” a few tiles away if you attack them and miss.
Thrill of the hunt.
Should giant flies also bleed some kind of acid or goop tile when hit? I know they do IRL when you swat them eww.
Can necromancer zombies also “leap” or “teleport” awat if attacked in melee?
I don’t know if they are nether/magical or scientific creatures.
Shrieker zombie can (lol) shriek in pain from any non-lethal attacks.
Is it possible for hallucinations to make you stumble (some kind of debuff) if you melee them?
I imagine vinebeasts would have a chance to disarm you if you attacked them with a blunt object.
The sludgecrawler and giant slug should also have a chance to degrade melee weapons when that becomes a thing.
How about the Jabberwock? Can it have a chance of intimidation (some kind of debuff) if you strike it weakly in melee?
Chopping up biollantes would probably get you covered in sap anyways.
Melee-ing robots should produce a loud noise since they are METUL.
That’s all I could think of. There are already some good ideas about the blobs and fungus.