BBC Sound Effects is a useful site that can be used to create resources. It can be accessed here.
As can be seen on the screenshot there is a ‘mixer mode’ where sounds can be chosen and played together to create a soundscape. Have a go at this here.
Combining sounds with images can be an interesting and creative activity. Here’s an example I have made, adding environmental sound to Georges Seurat’s painting ‘A Sunday afternoon on the Island of La Grande Jatte’. I have used a Google Slide. I’ve chosen and downloaded the sounds to Google Drive and then used ‘insert / audio’ to add them to the slide.
It would be possible to do this in Powerpoint, BookCreator and ThingLink.