Billy joined Halifax towards the back end of his career aged 34, and only had a short stay at the club, making just seven appearances.
Earlier in his career, Billy was signed by his former manager Neil Warnock, after Warnock left the Terriers for the south coast.
The midfielder had a successful time at Home Park, making a total of 137 appearances for the club in all competitions, he also gained promotion to the second division during his time there.
The Former Town defender signed at The Shay back in 2008 and stayed at the club for one season, making 20 appearances.
Before his time with Halifax, Barras spent a short time at Plymouth after joining the club on loan in 2002 but could only manage four league appearances.
Adamson is a former goalkeeper who started his career at West Brom and had a number of loan spells away from the club, one of which was at Halifax in 1999, where he made eight appearances.
His next loan move after Halifax was to Plymouth Argyle but he found first team football harder to come by just managing to play one match while at the club.
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