There's a reason for that. Slime moulds just aren't famous. They don't have any PR, unlike the tasty or toxic mushrooms, the annoying pin moulds and the ubiquitous yeast. But then slime moulds aren't moulds at all, because they aren't fungi. They are protists, single celled organisms, and can grwo very big for microbes. Some slime moulds occupy an area of several square metres and have a mass of up to 30g. Look for them on fallen logs where they chomp on the bacteria that are part of the decay process and look like brightly coloured slime patches.
The reason I love slime moulds is because they are just so odd. Most people now no longer encounter nature so readily as they used to. My family, for instance, had never seen a weasel until we saw one while visiting my mother's grave one day last year. For city dwellers, wildlife is often birds and foxes and little besides. That's a shame but I was brought up to turn over logs and stones to see what was beneath, and I spent a summer investigating the ponds and streams around my village, mostly in search of my second favourite life form, the planarian flat worm. But slime moulds are odd.
Some of them consist of a single cell with hundreds of nuclei. Sometimes they group together to form a slug-like entity that moves away and forms a fruiting body that releases spores. So there is an element of multicellular life in there and the evolutionary importance of such behaviour has not been lost. Not that we have entirely worked out the evolution of these things.
Anyway, look under or on logs in the future to see if you can find some slimy looking patches. They might be slime moulds.