I love love love love the Fulltone Fulldrive 2! I had one the first year it came out, and I used it as my main overdrive for about 10 years. I foolishly sold it when I started building my own pedals. Eventually I bought another one, and out of every overdrive I’ve bought or built, it’s still my favorite. I also love the Klon clone, but to me, it’s better as a boost than an overdrive.
They don’t make the FD2 anymore but you can get the 3, or the 1 on amazon: https://amzn.to/2AXboJK