Up to date, four. Illegal ones, ET, Alien and Predator.
Aliens
Yes, the three types of humanoid aliens are humanoid, non-humanoid and semi-humanoid.
XLR8
Cowboys and Aliens grossed $175,910,315 worldwide.
Aliens in the Attic grossed $59,551,283 worldwide.
There is no solid proof aliens even exist much less have visited Earth.
Cowboys and Aliens grossed $100,240,551 in the domestic market.
Aliens in the Attic grossed $25,200,412 in the domestic market.
No, only ecological types 9-17
Monsters vs. Aliens grossed $381,687,380 worldwide.
Alien grossed $203,630,630 worldwide.
I don't know about all governments but the US government claims to have no knowledge of UFOs or alien beings. But UFOlogists (people that study UFOs) have classified 4 distinctly different types of aliens.