Too many to mention. Some that spring immediately to mind: Joe Frazier-Manuel Ramos Joe Frazier-Terry Daniels Joe Frazier-Ron Stander Joe Frazier-Dave Zyglewicz Joe Frazier-Buster Mathis George Foreman-Joe 'King' Roman George Foreman-Crawford Grimsley ... Nobody was quite sure about Grimsley until he got knocked out in 13 seconds in his next fight. George Foreman-Lou "The Tuna" Savarese Lennox Lewis-Lionel Butler Lennox Lewis-Oliver McCall 2 Lennox Lewis-Henry Akinwande Lennox Lewis-Zeljko Mavrovic Larry Holmes-Gerry Cooney Larry Holmes-Carl Williams Larry Holmes-Muhammad Ali Larry Holmes-Leroy Jones I might even say Mike Weaver-John Tate. (When you have to explain who Tate was, it takes quite a bit of the luster off of it. Still, a great night for those of us who watched it live.) Didn't Don Dunphy call the first round of Frazier-Ramos the best first round he could remember since Dempsey-Firpo? You certainly don't hear that fight referred to with such glowing terms anymore.
"Ortiz didn't beat anyone in top 20 before or after Wilder fights" Jennings was 6th ranked by Ring and 19-1 when Ortiz outboxed him and KO'd him in 7. Jennings was coming off giving Wlad arguably his toughest fight in a decade over 12 rounds and had previously beaten top 10 Ring ranked Perez, along with stopping Szpilka, Fedosov and Liakhovich. Martin was probably top 20 ranked when a 42+ Ortiz KO'd him in January this year. Hammer was in decent form too and may have been top 20. Ortiz also hasn't lost to anyone in his career save Wilder.
The premise is flawed as it utilises the benefit of hindsight. The fact is the fights mentioned by the op were not forgone conclusions beforehand.
ggg vs Derevyanchenko ggg vs Szeremeta ggg and spence vs Brook mayweather vs Victor mayerather vs Gatti mayweather vs zab mayweather vs baldomir mayweather vs oscar mayweather vs mosley mayweather vs guerrero Plant vs Uzcátegui David Benavidez vs Ronald Ellis Hopkins vs Trinidad Oscar vs Whittaker
Crawford vs Indongo Crawford vs Benavidez Tank vs Gamboa Tank vs Barrios Crawford vs Felix Diaz Devin Haney vs Jorge Linares Lomachenko vs Campbell Luis Alberto Lopez vs Gabriel Flores Jr Usyk vs Chisora Duran vs Barkley Leonard vs Duran (2)
Irrelevant even if true. Your claim was that Ortiz never beat anyone within the top 20: 6th ranked Jennings definitely was and Martin coming off his career best win probably was. And if Ortiz beats Ruiz it will go down as the best victory for a mid-40's HW since Moorer-Foreman in 1994.