ecommerce-related domain - I let it expire and then got email from potential buyer if i'd want to sell it. Luckily i was able to re-register it to negotiate a ~$3k sale.
Another .COM domain i registered and never built anything and got a request to sell it. Time to hold before selling ~2 years. I was first owner.
1-letter .GG domain. $10k. Chinese buyer. Buyer paid for domain + Escrow.com fees. Spent about $800 to keep it registered before sale. While selling it - i received an offer for $12k for it :)
I am pretty good at finding decent domain names even when others think all good domains are taken.
PS: I was contemplating about registering GOO.GL domain when it was available. I registered GO.GL back then and run photography business off it for a couple years before letting it go.