The best movies indefinitely since I don't see any future movies getting that honour.
Logan
X2/DOFP was tied for me too. Most compelling superhero movies to date.
First Class and Deadpool are uncanny. The directors were superb with the films and never returned for any other movie , leaving a big mark on the series.
X1/Deadpool 2
Wolverine
X-Men 3
X-Men Origins
X-Men Apocalypse.