Leicester midfielder Dean Hammond has signed a new contract with the club after his previous deal expired.
Defender Steven Smith has joined SPFL Premiership side Kilmarnock on a three-year deal after his Rangers contract expired.
Just one game into a second spell in the Selhurst Park hot-seat, Warnock was charged with the task of identifying additions that could make a difference to his squad.
He was able to wrap up three deals before the window closed, with Zeki Fryers, James McArthur and Kevin Doyle acquired from Tottenham Hotspur, Wigan Athletic and Wolverhampton Wanderers respectively.
Warnock is delighted to have landed players he considered to be top targets, and those that he has admired for many years.
He said in the Croydon Advertiser: “We worked hard all day and managed to get three lads in.
“We had worked on Zeki Fryers for quite a while, he’s up-and-coming from Tottenham and has a lot to prove.
“He’ll be a good addition, a left-footer, and we’ve struggled in that position, not just since I’ve been here but for a few weeks.
“James McArthur, I’ve been after him for a while, he’s a super player. I remember watching him up in Scotland and kept in touch with his progress.
“I think he’s got a lot to prove as well. He’s back with the Scotland squad and he’s looking forward to starting. He’s just our kind of player.
“Kevin Doyle from Wolves, the deal is to January. He’s been up and down, but he’s one I think will fit into the squad we have.
“We have a great dressing room and he’s the sort of lad I’ve always wanted to manage. I have kept in touch with watching him and Shane Long for a number of years.”