There are twenty-three pair of shoes and slippers in the collection of English author Nick Foulkes (photographed for a Japanese magazine several years ago), and more than half of them are slip-on casuals. Including the horse-bit slip-ons in colored suede (I can't imagine where he can wear those around London).
If I compare Foulke's collection with my recommended shoe wardrobe, the choices are a bit more dandified. Instead of two pair of black oxfords he's got a pair of black half boots and a pair of brogues, which are another way to get through the week. Instead of two pair of brown oxfords he has another pair of half boots and another pair of brogues. His monkstraps are black, and he wears brown chukkas instead of bluchers. And then he's got all those slip-ons in addition to the basics.
I will admit to a bit of envy of the Edward Green Montpelliers in brown crocodile (front row, second from the left), but if I had a pair I'd never wear them.