The answer must be of course, the things we most want or desire. See these two articles for a great way of enabling us to reduce spending on items we only use infrequently or once, and also therefore prevent our homes getting cluttered up with more stuff. We should all be pushing to get these set up in our own neighbourhoods. Verdict? I like.
The share shop https://www.theguardian.com/society/2015/may/13/frome-share-shop-social-enterprise
Library of Things https://www.theguardian.com/sustainable-business/2016/aug/23/library-of-things-peak-stuff-sharing-economy-consumerism-uber