Here we take a look at their best players who arrived on a free transfer and went on to make telling contributions. We feature those signed since 2010.
1. Tomasz Kuszczak
The goalkeeper arrived from Manchester United in 2012-13. The Polish keeper made 84 appearances for Albion and left for Wolves in 2014. He's now 38 and is at Birmingham.
2. Bruno
The right back signed from Valencia in 2012-13 and went on to become a hugely popular figure on the south coast. Retired in 2019 having made a very impressive 225 appearances for the Albion. Now, 39, and a key man in Graham Potter's coaching set-up
3. Liam Rosenoir
Signed from Hull City in 2015-16 and made 44 appearances for Albion. An accomplished defender and now first team coach at Derby County.
4. Matthew Upson
The centre back and former England international arrived from Stoke City in 2013-14. He made 18 appearances on his initial loan period and another 43 follow his free transfer. Moved to Leicester in 2014 and the 41-year-old is now a respected pundit on the beeb.