Options will be the most cost effective method plus you have a predefined gain/loss profile. You said that this is not available for every security in your portfolio, so let's address those.
From a 30,000ft view, you can buy inverse ETFs on the indices where your securities reside or even put options on the index itself. While this is good for a generic market downturn, it doesn't come close to a perfect hedge.
For your individual securities, you want to think about the risks to those securities. Do you own mining companies where cost of capital is a major risk to the company's profitability? You can buy put options on sector-specific ETFs, use interest rate futures contracts, or even sovereign bond ETFs. I realize there are a lot more risk factors pertaining to a mining company, but this is to give you an idea of how you want to frame your thinking when analyzing your portfolio.
Since you don't want to transfer the securities and realize a capital gain, a lack of optionality in your portfolio doesn't hurt you all that much. You won't be at risk of getting assigned/auto-exercised since you can't buy options on the securities in the first place.
D Stanley makes a good point which is, no matter how you hedge (whether it be at a sector level or on the asset level with direct options), you are selling off some upside for downside protection.
Your last statement is really important. It is imperative to understand how liquid your hedges are. Some ETFs with optionality have great liquidity and therefore should operate as intended in a market downturn while some do not. Hedging at a sector level on an ETF with very illiquid options is usually more risky than hedging with asset-specific options. The caveat to this being the stock could be just as thinly traded as the options on the ETF.
Tying it all together: think about the risks to each security in your portfolio on an individual level AND on a portfolio wide level. Ask yourself, am I allocated too heavily to sectors/securities with high interest rate risk, high geopolitical risk, etc. Finally, when hedging at a portfolio level, Bob Baerker makes a great point which is that you want to reduce your overall correlation.
Hope that helps.