Pretty sure this is Diurnea fagella - has those odd enlarged third thoracic legs. Found this feeding in a spun tent on hazel.
This is a hoverfly larva, and probably a Syrphus/Eupoedes sp.
Harlequin Ladybird larva - found loads of these.
And this spectacular thing is a powdery mildew on oak - Erysiphe alphitoides