Basically, I remember having this old paperback (which was apparently published in the 70s, although I think my Dad got it second-hand) which was a small anthology of various fantasy/sci-fi/horror short stories for young adults (of course it was published in the 70s so it was better written than most YA stories today). I live in the UK and I'm assuming this short story collection was only published in Britain.
I remember quite a few weird stories in it, the ones I remember best were:
A story where a prince in some Middle Eastern(?) fantasy land has to try and bargain between two dragons, one of them represented fire (as in, it actually lived in and was made of lava) and the other represented the cold and was made of ice. The story features the hero tricking both dragons into fighting each other, thus getting rid of their presence and saving his kingdom or something.
One story where an alien creature ends up in a small British town (and is described as being shaggy-furred, multi-eyed and having a "metallic" stench) but is encountered by a young boy.
Another story where two girls awaken a (not actually evil) gargoyle at their church, which follows them back to their house. They desperately try to cover up its existence and try to get it out, until they realize that it can leave when it's told to "fly home" rather than "go home".
Another was about a pair of kids who come across some wizened old harpies who just want to fly home. The harpies are encountered having a picnic (even describes the harpies eating the wasps that tried to get at the jam).
And finally (and my favorite of them all) is a tale that involves the spirit of an evil brontosaurus (specifically, a brontosaurus who used to torment other dinosaurs and whose spirit swore revenge on mammals when a rodent twisted its corpse's tail) being dug up and then possessing a mobile crane. Yes, an evil construction crane possessed by a dinosaur ghost, which goes on to wreck the local seaside town until the manager tricks it into driving into the sea. There was even a creepy illustration showing how the crane's grabbing bucket had turned into a reptilian face and mouth. It is not Theodore Sturgeon's Killdozer. This one was definitely had a big focus on dinosaurs - it even described the dino ghost admiring the appearance of the crane before taking it over.
Sadly the book is buried in one of the cupboards in my old house, and I can't remember the name of it at all, and Google's been no help at all. Has anyone else here possibly read them? I remember the cover being a painting of a red dragon sitting in a volcanic landscape of lava, if that's any real help