Saving you a click, here's the list:

Asteroid City (2023)
The Andromeda Strain (1971)
The Prestige (2006)
Paprika (2006)
Under the Skin (2013)
Stalker (1979)
Westworld (1973)
Dark City (1998)
Ad Astra (2019)
Annihilation (2018)
Attack the Block (2011)
Solaris (1972)
Life (2017)
Silent Running (1972)
Soylent Green (1973)
The Mitchells vs. The Machines (2021)
The Iron Giant (1999)
Repo Man (1984)
La Jetée (1962)
They Live (1988)
Them! (1954)
The Thing From Another World (1951)
Ghost in the Shell (1995)
Donnie Darko (2001)
Nausicaa of the Valley of the Wind (1984)

With the exception of Them! or Life, I'd argue that none of these are particularly "underrated". To reach that category, I'd say that a movie would need to have a less-than 60 rating on Rotten Tomatoes or other similar review aggregation site to demonstrate some degree of negative or "meh" critical consensus.

Case in point: Enemy Mine (1985).