National Insect Week returns in 2020
A range of resources from the RSPB including 'Spot it! sheets' on Minibeasts, 'Food and water' for Butterflies, 'Homes for insects' and 'Nature Detective Equipment' for catching insects.
There are lots of contenders here – possibly the pretty red and blue rove beetle Paederus – very, very tiny amounts of its poison have been used to cure chronic ulceration in people. Ladybirds are pretty poisonous (and pretty) and can bleed foul-tasting poisonous brightly coloured blood from their knees.