It could be a busy summer for Everton as they look to keep adding to their squad to make themselves a continued threat for the European spots in the Premier League.

There's been plenty to positive about from this season for the Toffees but there is still work to do and it'll be interesting to see what they aim to do this summer.

With that said, here are nine developments we could see in the blue half of Merseyside this summer...

Aarons is being linked with a lot of clubs at the moment after Norwich City achieved promotion from the Championship and he was a key part of that.

The Yellows return to the Premier League for next season but that might not stop Aarons leaving the side with Everton among those interested.

The Times is among those to have reported the Blues' interest of late.

Sasa Kalajdzic is a player that would benefit Everton if he joined, according to Bundesliga insider Daniel Pinder who was speaking to Football Fan Cast.

The striker has been likened to Dominic Calvert-Lewin in the way he plays and could be an option for the Toffees if they look to add to their attacking options.

Budging DCL won't be easy, though.

Hwang Hee-Chan has said that he will discuss his future with Red Bull Leipzig in the summer with Everton linked with the player.

Leipzig are seeing a manager change with Jesse Marsch coming in for Julian Nagelsmann who is off to Bayern Munich and, naturally, Marsch will have his own ideas.

Hwang has already said he knows Marsch and that could be an adavantage.

Toney is being linked with Everton, among other clubs, by The Athletic.

He's had a fabulous season in the Championship with him scoring 30 goals so far and there is a good chance he'll hit more in the play-off battle.

One way or another, he'll be a top flight striker next year.

Rabiot is of interest to Everton according to TuttoJuve, via HITC, with Juventus seeing their league dominance in Italy ended at the weekend by Antonio Conte's Inter Milan.

He's a player that has been at the highest level for a while with him spending time on the books of Juventus and PSG in his career and is the sort of player Everton naturally want to be looking at as they continue to try and improve.

Aguero is heading for the Manchester City exit door after a hugely successful decade at the club and it could be Everton where he ends up.

That is the view of the Daily Star, who suggest the Toffees are looking at bringing the multiple Premier League winner to Goodison Park.

Certainly, he would be some signing even if he is getting towards the latter stages of his career.

Koulibaly and Yerry Mina could be part of a swap deal in the summer window, according to Football Insider.

Koulibaly has been repeatedly linked with some of the top clubs in Europe of the years so it's a sign of where Everton are aiming by looking at him.

Indeed, a swap with Mina could potentially happen, though that would be quite the significant transfer if it did happen.

Besic is set to be leaving Goodison Park before too long.

The midfielder has been out on loan at the likes of Sheffield United in the recent past and it seems as though he is not at the level that the Toffees want.

He's a good player, obviously, but the Blues are aiming higher.

Kean has had a good time at PSG out on loan and there is every chance they will want to keep him and he will want to stay.

He's clearly a very talented young footballer and Everton will know that but are they going to get the best from him?

It's a judgement call they need to make.