Say, for instance, diamonds, or gold? Watches?
Wine is often invested, as is whisky and some other spirits And fortified wines that have particular vintages, such as port. You need to be particular about which ones to invest in though.
Top vintages of wine and port can rocket in value, to make the big profits you need to buy the new vintage before everyone realises it is going to be a top year and sell it some years later when it is approaching its peak. This is obviously quite tricky to do.
It is fairly common to buy a share in a particular batch of whisky (proper Scottish single malt), then after 12-18 years when it is matured you can take your share in bottles or cash.
I think you would be better asking about what things COULD increase in value. Even the given example (houses) are not certain to increase in value. In fact, one of the key causal factors of this recession IMHO is that no one realized that partly because there have been few recent housing busts, and also the illusory effect of inflation that made it seem like houses always increase in value.
I once heard it described that rich people tend to get richer because they spend more of their money on things that are more likely to hold their value or appreciate (houses, art, etc.) as opposed to poor people who spend the majority of their money on consumables like rent, utilities, food, cars, etc.
- A truly classic automobile.
- Art or antiques
- Sports cards (and some trading cards)
There are lots of thing that people will pay for if you wait long enough. I don't know that I would consider them investments, but they go up in value.
In the US, the "first class forever" postage stamps. The post office has never lowered the cost of a stamp, but has raise it several times recently. Given that the gov't has bailed out everyone else, I believe it is a safe bet that they would bail out the post office if it financially fell apart.
And you can always use them to send a letter.
They aren't very liquid, and it would probably be difficult to invest in them in large quantities. Although, when the post office does raise rates, you could sell yours off on ebay or something.
For an investment to appreciate in value, one of two things needs to happen: 1) Demand for that particular item needs to increase. 2) The supply of that item needs to decrease.
Houses are good because everyone needs a place to live, but there is a finite amount of land. No matter how much you invest in Manhatten real estate, Manhatten ain't growin'. The trick there is to find an area that people are going to want to live in when you're ready to sell. Specific vintages of wines and spirits are another good example, because it's literally impossible to create more of that vintage.
Cars, and most consumer goods, usually don't appreciate because they don't last long enough. Most cars are resold within three to five years after the initial purchase. This is also why jewelry is a good investment; properly cared for, it can last centuries without wearing out.
So, look for something durable that has a limited supply.
All of the above mentioned items might appreciate in value (gold, wine, art). However your house is still the only asset that can appreciate TAX-FREE (no capital gains tax to pay when you sell your principal residence).