All of my suggestions fit those lol. But it seems the op wants to release them into his pondOp said something that would be comfortable in a 250-300 gallon. 99% of the fish listed so far would not be unless you plan on releasing them into your pond.
For that tank and for aggressiveness you are looking at bullheads, green sunfish, rock bass, perch, pickerel.
If you are releasing them into the pond eventually, sky is the limit on basically all US and EU native species
Redear sunfish have the capability of getting a foot and a half, bluegills around 16"Here's a long list: (I underlines a few that interests me)
Sturgeons - 192"
Paddlefish - 60"
Flathead catfish - 48"
Blue cats - 46"
Northern pike - 30"
Koi - 36"
** Bowfin - 30"
Carp - 31"
Salmon - 30"
** Channel cats - 22"
Smallmouth bass - 16"
** White Sucker - 18"
Quillback - 18"
Brown Bullhead Catfish - 20"
White Crappie - 20"
Spotted Sucker - 20"
Utah Chub - 20"
Yellow Bullhead Catfish - 18"
Trout - 18"
Walleye - 18"
Longnose Sucker - 16"
Black Crappie - 16"
Black Bass - 16"
Largemouth bass - 16"
** Yellow Perch - 15"
Redear Sunfish - 14"
** Black Bullhead Catfish - 14"
Needle nose gar - 12"
Lake Chubsucker - 11"
** Warmouth - 11"
Mud Sunfish - 10"
Spotted Bullhead Catfish - 9"
Pumpkinseed - 9"
Green Sunfish - 9"
Longear Sunfish - 9"
Green Sunfish - 9"
Bluegill - 8"
Pond loaches - 6"
Orange Spotted Sunfish - 6"
Dollar Sunfish - 5"
Spotted Sunfish - 4"
Logperch - 3"