Barnsley have signed ex-Chelsea forward Milan Lalkovic on an 18-month contract and Manchester United midfielder Ben Pearson and Stoke striker George Waring on one-month loan deals.
Lalkovic, 22, spent last season on loan at Walsall and joins the Tykes as a free agent after being released by Czech Republic side FK Mlada Boleslav.
Pearson, 20, is an England Under-20 international.
Ex-Everton youngster Waring, also 20, is yet to play for Stoke's first team.
Pearson and Waring could feature for Barnsley in Saturday's game against Yeovil, along with Chelsea striker Alex Kiwomya, who joined the club on loan last weekend.
However, Barnsley are still waiting for clearance for Lalkovic.
"We've been a little bit thin on the ground this last few weeks with injuries and players going back to their parent clubs," boss Danny Wilson told the club website.
"We needed to bulk the squad up but what we've bulked the squad up with is quality - it's not just filling gaps with players just to fill the gaps and not be able to affect the team."