SELECT *
  FROM      (SELECT f1, f2 FROM tbl1 WHERE f3 = '2018') AS t1 
  LEFT JOIN (SELECT f1, f2 FROM tbl1 WHERE f3 = '2019') AS t2 ON t2.f1 = t1.f1
  LEFT JOIN (SELECT f1, f2 FROM tbl1 WHERE f3 = '2020') AS t3 ON t3.f1 = t1.f1

DECLARE @yr AS INT = 2018

SELECT *
  FROM  (SELECT f1, f2 FROM tbl1 WHERE f3 = @yr) AS t1 

WHILE @yr <= YEAR(GETDATE())+1
 BEGIN
   SET @yr = @yr + 1
   LEFT JOIN (SELECT f1, f2 FROM tbl1 WHERE f3 = @yr) ON f1 = t1.f1
END

select 
  -- 2018
  f1 
  , f2 =  max(case f3 when 2018 then f2 end)
  , f3 =  max(case f3 when 2018 then f3 end)

  --2019
  , f1 
  , f2 =  max(case f3 when 2019 then f2 end)
  , f3 =  max(case f3 when 2019 then f3 end)

  --2020
  , f1 
  , f2 =  max(case f3 when 2020 then f2 end)
  , f3 =  max(case f3 when 2020 then f3 end)
from ... 
group by  f1