I totally agree with a) and b), I just really like Gladiator.
Those are amazing lists but I’d add District Nine, Sixth Sense, the Glass trilogy, Psycho, Capernaum, Avengers, Black Panther, The Secret Life of Walter Mitty, Unbroken, 2012, Lion King, and Arrival.
My personal top 5 favorite movies are:
1. Forest Gump
2. Shawshank Redemption
3. Gladiator
4. Arrival
5. Sixth Sense
Though some honerable mention would go to:
The Prestige, District Nine, Capernaum, Inglorious Bastards, The Revenent, and Amadeus