If we're talking strictly Z, then Piccolo >
Krillin gives Tien a run for his money as well.
Piccolo, Krillin, and Tien were all top 5 material in the OG dragonball, and both Piccolo and Krillin got some serious power boosts after Namek in Z (Nail fusion, potential unlock)
If none of the saiyans EVER existed, then Tien would be a much liklier candidate. Not really sure how strong Krillin would have gotten under Roshi's training, or if he would end up getting murked in the King Piccolo saga (since with no Goku, there would be no power pole for Krillin to have gone back looking for, which means no Tambourine surprise attack)
Tien, Roshi, Krillin, and King Piccolo would all be in the running.
Wasnt Tein last man standing against Nappa?
Yea he def would be the strongest.
Nope, Tien got his arm ripped off and died after blowing Nappa's armor off. Krillin was the last man standing after the whole Saiyan fight ended. (He was also the only one to draw blood in the Nappa fight until Goku arrived.)