Bettors

13 clues
O.T.B. users
Reno raisers
Pool parties
Pool habitués
People in a pit
Tote board readers
Racetrack regulars
Racetrack habitués
Some trackgoers [18]
Everyone in the pool
Ones placing trifectas
They lay it on the line
Those who may accept tips
Similar answers:
Abators
Abdicators
Abet
Abetment
Abets
Abetskramer
Abetsongs
Abettal
Abetted
Abetter
Abettermusetrap
Abetters
Abettertomorrow
Abetting
Abettor
Abettors
Abetvigoda
Abnegators
Actofbetrayal
Actors