This study investigates the safe haven, hedging, and diversification properties of oil, gold, and two cryptocurrencies, including Bitcoin and Ethereum, for equity investments in the G7 economies under different market conditions. Daily data covering the pre- and post-COVID-19 periods were employed, using the linear and nonlinear Generalized Autoregressive Conditional Heteroskedasticity models. The empirical evidence supports gold as an undisputable diversifier for equity investments in the G7 equity markets under all market conditions. Cryptocurrencies have a valuable safe-haven potential, particularly during the COVID-19 crisis. Furthermore, the suitability of the optimal hedge asset depends on market conditions and individual countries, where the traditional assets present the best hedge in the normal conditions, compared to the modern assets. However, in the stress periods, Bitcoin presents the best hedge for the stocks of the G7 European and the UK countries, although Ethereum is the optimal hedge for the U.S. and Canada. In contrast, oil exhibits a superiority in hedging Japanese equities during all market conditions.