Funny but ironic, b/c your list is actually in reverse order, from low to high risk, not high to low. The lowest risk thing to do is actually just buy BTC & ETH and let the associated frenzy of ICOs and cryptoassets drive them higher while remaining relatively liquid and legal. #2 - #4 are sequentially higher risk from potentially illiquid (tokens) to grey area (ICO) to illegal, and the SEC has shown they have patience, reach, and savvy.