Amusingly KaZaA itself was one of my first experiences using an “alternative” client for something. There was KaZaA Lite which removed the bundled Cydoor malware, K++ which added hax features like unlimited searches and forced 1000 node reputation, and the most famous KaZaA Lite K++ which did both. Lots of others too like “KL Extensions”, K-Sig, K-Dat, but those were the two big ones.