This all depends on what timelines you work on, how many assets you are trying to protect.
Alternatively you protect yourself by lowering your dependence on steady income.
Ads from the World Gold Council are becoming very frequent, targeting consumers. That must mean something (looking for exit liquidity)
Also (not a financial advisor), when a crash occur there is a so called "flight for quality" where people move money they made by cashing out the assets to stable (A+ assets). So look for companies that have solid financials and can weather the storm.
Finally, diversify not only on the industry, but also geographically. EU, Swiss, Asian. I personally stay a bit away from emerging markets stuff as I don't have enough knowledge to make informed decisions (I don't even consider Emerging Market ETFs which should be run by SMEs).