Adrien Rabiot
Rabiot would be a typical Wenger signing. Not necessarily filling an immediate need, but a young player that Wenger likes and clearly sees potential in. He is the stereotypical versatile attacking player that Wenger loves to add to his side. He would come at a cheap price due to his expiring contract.
Reports have already been circulating for weeks that this deal could be completed sooner rather than later.
He is a player that is young, versatile, excellent in attack, and does not fill an immediate need (depending on the future of Lukas Podolski and the so far worrisome form of Santi Cazorla this season). Rabiot would be a typical Wenger signing and I love it.
Matija Nastasic
Another young center back that would fill the void as the back up center back. Nastasic would be an ideal signing. Yes he has been injury prone and makes mistakes but he has youth on his side and Premier League experience.
Nastasic’s potential is there, he just has to stay healthy and play consistently. Nastasic would be a better signing than Manolas due to his experience in the Premier League and his experience playing for a successful top side.
I don’t know if this transfer is a no-brainer as it is yet to be seen if Arsenal actually have an interest in the young Serb, however Wenger has made worse defensive signings (think Mikael Silvestre, Sebastian Squillaci, Andre Santos, and even Pascal Cygan to a certain extent).
Toby Alderweireld
This would be a sensible signing in my opinion. Alderweireld has been made available from Atletico Madrid after it was made clear to him that he would not be considered a starter.
He is 25, so it a good age where he is mature and experienced enough to contribute to Arsenal. He is also versatile as he can play both right back and center back, which would allow Chambers to play in multiple positions and develop. He would not come at too high of a price; rumors say he is available at 12 to 18 million pounds. The only issue is that he would likely be in the same position at Arsenal and serve as a back up, which is why it is reported he wants to leave Atletico.