#6. Robert Roode - Signed with WWE in 2016
Robert Roode had an incredible 12-year run with IMPACT Wrestling/TNA. He was a key tag team figure, but he also won the World Championship twice, with one reign being the longest in the IMPACT Wrestling World Championship lineage.
He was signed by WWE in 2016 at the age of 39. It was a bit late, and Robert Roode could have had a longer WWE run had he signed in his prime. However, he had a very noteworthy run with IMPACT Wrestling.
#5. Adam Cole - signed with WWE in 2017
Adam Cole's NXT debut seemed like a long time ago. It's been over three years and he has remained a staple feature of WWE's third brand. He's still only 31 years old and we don't doubt that he will be a part of WWE's main roster (and a key figure at that).
He remains one of the few Superstars on this list who could have signed with WWE at an incredibly young age. He was with Ring of Honor from the age of 19, until 2017 where he signed with WWE.
Adam Cole was always viewed as an exceptional talent for years, and in the eyes of many, he would inevitably become a big star in WWE. However, signing at the age of 28 turned out to be far better than jumping ship while he was younger.