For a long time, Waqar Younis was the only who had crossed this barrier. Later. “GOAT” Lyon caught up, and now Kemar Roach:

There are as many as 54 Test players who have made 1000 runs without scoring a century. Some have managed a century practically at the end of their Test career (e.g. Kumble, Vaas).
Today there are three players with 2000 runs and no centuries:

Warne’s 3000+ looks safe here, unless Dickwella plays long enough without a century. He does hold the record of 18 fifties without a century, ahead of Chauhan with 16.