The best replacement for stalker is fallout.

The best alternatives to stalker are rated as following:
★★★★★  fallout
★★★  metro
★★★  quickdraw
★★★  stocker
★★★  spellslinger
★★  roach
★★  metro 2033
★★  dragoon
★★  marauder
★  steady aim
★  assassin cross
★  quickdraw cod ghosts
★  teebird
★  esper
★  creeper
★  obsessed
★  fallout 3
★  zealot
★  secret admirer
★  marksman
★  far cry
★  mutalisk
★  hydra
★  bioshock
  sitrep
  jugs
  browning hunter
  samick sage
  stalker
  fnar
  demon stalker
  quickdraw ghosts
  hopeless romantic
  jugs radar guns
  admirer

Your alternative for stalker is not listed? Suggest!
Speaking about stalker, one probably shouldn't forget about lurk.

Other search terms related to stalker and their ratings are:
★★★★★ lurk
You have in mind a companion for stalker and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of stalker in all years. Click on graph for more.
stalker
fallout
metro