Obviously this is subjective to a degree and we don't know who is on your list.

Spud Carroll?
Brett Mullins?

John Gallagher and Mark Brooke Cowden, both All blacks.

saw gallagher in the sts and hull games

Gallagher was taking his time to settle in to league after his converting from union but was showing some true class on attack. True his defense was a lot slower at coming up to speed but then he got spear tackled (at Saints iirc) and it finished him as a player. Never the same after that

But an absolute star and game changer at Halifax

Maybe it's just my memory but I just cannot remember him for the life of me, having stellar performances at Wigan,or at Halifax subsequently.His records at both clubs seem pretty similar.I recall an audience with Graham Murray (after Stevo was fawning over how he could spray the football all around the park),and Graham just said Stevo was talking bull**** Florimo just had a big handoff in his armoury and that was it.