Pretty much every proven big game bullet offering reputable penetration/expansion/weight retention is available in a 6.5 load. If your typical hunt is taking shots inside 300 yards, any number of loads will work well, and likely group well on paper also.
Hornady Precision Hunter 143 gr ELDX is what I shoot for deer. 1/2″ 5 shot groups if I do my part. Have only filled 1 tag with that bullet so far though and it was only a 105 yard shot so no feedback yet on the performance at distance. Hopefully I’ll draw at least 1 antelope tag here next week and can put that round to work at 300-500 yards. The 143 gr eldx load is probably one of the most popular selections for 6.5 guys shooting big game though.
I think the only round I’ve shot at the range that didn’t produce 3/4″ groups or better at 100 yards was the american eagle 120 grain load. That shot 5 shots at around 1″. Saturday I’ll be shooting some Sig, Barnes, & Hornady match grade target loads as a bunch of us are getting together to fire on 300-600 yard targets.