Jamieson, Fausset and Brown on Job 21:29

29. Job, seeing that the friends will not admit him as an impartial judge, as they consider his calamities prove his guilt, begs them to ask the opinion of travellers (La 1:12), who have the experience drawn from observation, and who are no way connected with him. Job opposes this to Bildad (Job 8:8) and Zophar (Job 20:4).

tokens--rather, "intimations" (for example, inscriptions, proverbs, signifying the results of their observation), testimony. Literally, "signs" or proofs in confirmation of the word spoken (Is 7:11).