A lot of these heroes wouldn't be allowed... even though "fictional" people can be summoned as heroes, a real person serves as their base. In the example of Fate's Assassin, the premise is that Kojirou didn't actually exist, so a "nameless swordsman who was capable of performing his famous technique" was summoned in his place.
God of War
Guan YuSword Demon
Dugu QuibaiCelestial Archer
HouyiTypo: It should be 后羿.Human Butcher
Bai QiDivine CondorIt's the moment to witness a miracle.Saint Thief
Bai ZhangtangA character parodied from Bao QingtangThe Great Saint Equal to Heaven
Sun WukongLu ChenA renowned magician from Taiwan