It turns out that after a first batch of 10 domains, which let's say I "invented" (youcoin.eth, kalifornication.crypto, nftpanda...), thinking they were the ultimate Coca-Cola of the desert, little by little I found websites where I could get an idea of what domains to buy.
And there I stumbled upon the PREMIUM domains page of Unstoppable Domains, properly organized and with the sales prices. Seeing that many had been sold, and for many ETH, I decided to buy ABSOLUTELY all the domains that, in their version of ENS Domains, were available (for €5 per year). The vast majority were words I didn't even know, but I did know that someone had paid a lot of money for their .crypto versions.
Over time, Dapps and sites appeared where you could optimize your purchases and choose from absurd collections (and with them, by the way, the decline began), even valuation applications, but for me having that information from UD was the key to my success (I have an average of around $150 profit per domain). So much so that, like good magicians, I took great care to keep it quiet...
Greetings! ;-) 
By Borja Moskv | X | Farcaster
