Yeah, the Internet tells me there were 201 issues of DHP across all 3 of its runs (to date), and here's a complete list of Aliens/Predator/AvP stories from Dark Horse Presents:
Alien
- Theory of Alien Propagation (DHP #24)
- The Alien (DHP #56)
- Reapers (DHP Fifth Anniversary Special)
- Incubation (DHP #101-102)
- Once in a Lifetime (DHP #140)
- Headhunters (DHP #117)
AvP
- The Web (DHP #146-147)
Predator
- God's Truth (DHP #46)
- Demon's Gold (DHP #137)
You might be thinking of the "Dark Horse Comics" serial anthology series, which also had a bunch of A/P/AvP stories too. DHP was always in black-and-white, DHC was always in color.