There's other artists with great 4 albums runs, most of which have already been mentioned. Tribe, De La, Face, PE, etc. But none of them are better than Kendricks run in my opinion.

Nas, I'm maybe the only person who likes I Am more than IWW, but Nastradamus is garbage and Illmatic is the only real classic (again, I know everybody else rates IWW).

Ghost, Bulletproof Wallets is bullshit. Even the bootleg version wouldn't stack up.

Oddissee, doesn't fit the parameters of the OP (true great), also he's not outstanding at anything. When his albums drop, they might get a spin or two and then I forget about him. He's not memorable enough. If we are just naming any artists rather than sticking to the greats, then Cunninlynguists would have a better claim than him, even if they were still quite raw on Southernunderground.