Some of them do, a bit, such as:
A blessing of unicorns: imagine them as priests blessing a marriage
A caravan of camels: imagine a camel family off on their hols in a car towing a caravan. Will their humps stick out of the sun roof?
A crash of rhinos: I love the picture in my head of rhinos galumphing through the African bush, crashing into everything, including each other
Let's be more creative
A good starting point is to choose some types of people:
Professions: used car salesmen, barristers, footballers...
Hobbyists: detectorists, dog walkers, astronomers...
Various personality types: positive, talkative, over-friendly...
... and find a gently mocking way of briefly summing them up.
my starting point
So, having chosen positive and negative thinkers as my theme, I'll consider the sorts of things these people say or do, and bring these words / actions more or less directly into the gags.
My 'collective noun gags'
A 'that'll never work' of pessimists
A 'you and whose army' of nay-sayers
A 'rosey tint' of optimists
Do have a go at this. I hope you have fun doing it!
I'll end today by asking you if you can think of a new collective noun for collective nouns.
Here's my answer: a collective.
Thanks for your visit!