Sussex spinner Will Beer, wicketkeeper Callum Jackson and all-rounder Steffan Piolet have signed new one-year deals.
Beer and Piolet, both 26, were regulars in one-day competition last season but Jackson, 20, did not feature despite making seven appearances in 2013.
"Both Will and Stef will be hoping to make further inroads into red-ball cricket," Sussex cricket manager Mark Robinson told BBC Sussex.
"We will try to develop their skills so they can play across all formats."
Robinson was pleased with the contributions of Beer and Piolet in one-day cricket, where they took 20 and 23 wickets respectively.
|Sussex manager Mark Robinson:|
|"Ideally we want to be able to play four seamers. That is the strategic goal. We think we have got a good, competitive squad."|
"Will has done well in one-day cricket with the ball for a while but made a bit of a breakthrough with the bat this year," Robinson added.
"Stef is a good performer in white-ball cricket and his stats as good as anybody's in the role he does."
Eastbourne-born Jackson scored 653 runs at an average of over 40 for Sussex's second XI in red-ball cricket in 2014.
"The challenge for Callum is the potential of Matt Prior and Ben Brown in front of him," Robinson said.
"We made him fully aware of that and that we would totally understand if there were opportunities to be taken elsewhere. He is a cricketer we do think very highly of and he is definitely a young man with a future.
"Also nobody is 100% certain of what will happen to Matt down the line. We hope he makes a full recovery and he might get back in the England team."
Sussex have signed seamers Tymal Mills and Ajmal Shahzad already this winter, while fast bowler Lewis Hatchett is yet to sign a new contract.
With batsmen Luke Wright and Luke Wells extending their deals at Hove, Robinson says his plans for 2015 are starting to take shape.
"Ideally we want to be able to play four seamers. That is the strategic goal," the 47-year-old said.
"In order to do that you need one of your batters to bowl very good seam or your spinner to be able to bat at number seven or eight and get enough runs.
"It's OK talking about these things in November but come April and May you need your key players fit, the right amount of bowlers to take 20 wickets and batsmen to score runs to allow the bowlers to start to dictate the game."