Forwards

Left winger: Cristiano Ronaldo (Real Madrid & Juventus, Portugal)
How do you even stop this guy? Two leagues have tried (this year), but there's still no way. Ronaldo kicked his level up a notch in 2018, as Real Madrid brushed off their insipid league campaign to clinch another European crown. Then he scored some goals in Russia, and as of now, he's lighting it up in Italy.
The Portuguese has scored 47 goals this calendar year. His goalscoring exploits have not been affected by a change in scenery, and he has scored 10 for the Italian Champions already. He has altered his game to cope up with his ageing body, and he has done it magnificently.
Striker: Lionel Messi (Barcelona, Argentina)
It's ironic to say, but Messi's unwavering levels of excellence have actually been detrimental for him. The Argentine was placed 5th in the Ballon d'Or ratings, but the year he has had deserved so much better. Messi recorded 51 goals and 26 assists in 2018, and his contribution to 77 goals is bettered by no one.
He starred as Barcelona clinched the league and cup double in May, and the Catalans are on course to repeat their LaLiga success this time. His World Cup campaign in Russia was cut short in the round of 16, but judging a whole year by 4 games isn't fair, is it? Messi has played before in the 'false nine' position, and his position has been deep under Ernesto Valverde as well. With Ronaldo and Salah to run behind him, this attack can cause havoc.
Right winger: Mohamed Salah (Liverpool, Egypt)
The Egyptian had a 2017/18 season to remember, and he has continued that form. Salah's goal tally last season was bettered only by Messi, as he set the record for most goals in a 38-game Premier League season.
He is on course for the crown this campaign as well. Only Pierre-Emerick Aubameyang has scored more league goals than Salah's 13. Liverpool are 6 points clear at the top of the table, and his goals have been a major reason why. Salah has had a stellar calendar year which no one really expected, and aged 26, he still has a long way to go.