Here are some example of players the Rays have acquired over the years, who end up having a career year or more with them. Please feel free to add more names. An equally long list could be complied of very good Rays players that were traded, sometimes in or before their prime, who went on to stink for their new teams, including Carl Crawford, Archer, Kazmir, Cobb, Odorizzi and now, apparently Blake Snell.
Carlos Pena
.789 in 7 seasons prior to TB
1.037 in 2007 (a year after playing for the Sox at .776)
.871 in 2008
.893 in 2009
He dropped off after those 3 seasons (.723) with some being with the Rays.
Jason Bartlett
.702 with MN in 5 seasons (only one over .700)
.879 the second year with the Rays in 2009 (.752 in 3 years.)
.591 with the Padres after being traded to them for 4 prospects in 2010.
Rafael Soriano
2.92/1.037 WHIP in 8 good seasons before TB
1.73/0.802 in one season with TB (2010)
2.94/1.215 in 2 years with the Yanks
3.15/1.181 in 2 yrs with WSH after NYY
3.13/1.206 total after leaving TB
Steve Pearce
.756 from 2007-2015
.729 w BAL in 2016
.908 w TB in 2016
.768 after leaving the Rays, although he did very well in 2018 TOR/BOS
Logan Morrison (L0ts of 1Bmen do well in TB)
.742 pre TB
.813 w TBR '16-'17
.636 after TBR
Tommy Pham
.828 w STL pre TB
.870 w TBR '18-'19
.695 after TB
CJ Cron
.756 LAA
.816 TBR '18
.789 after
Travis d'Arnaud
.707 in 7 years with the Mets
.783 in 2019 w Rays
.813 w ATL after
Last but not least, another ex Sox...
Casey Kotchman
.717 pre TB, including .572 w BOS in 2009
.800 w TBR in 2011
.589 after and out of baseball in 3 years after leaving (only age 30).