A long time ago back at Brandywine Raceway, Meadow Blue Chip used to compete against males all the time in the feature race, so did Miss Conna Adios. As for trotters, Fresh Yankee always did well against males. Fresh Yankee was a $900 yearling purchase who won almost 1.3 million back in the 60's which would be the equivalent of over 10 million in 2025 without factoring in inflation.
great memory with Meadow Blue Chip
she raced in the open/invite at Brandywine/Liberty Bell in the 70s when I first started going to the track
there was no Open mares that would fill in those days-so she was forced to face the boys and beat them more often than not
Moni Maker raced until age 7 and her accomplishments were already mentioned on another thread, beating the boys both here and many races in Europe
if we were talking fillies-it would be CR Kay Suzie-who was more than 10 lengths faster than the boys in her 3yo season--you will not see another filly go off 1/9 in The Hambletonian ever again