Like more than one of them
21 games close to two or more of Sid Meier's Railroads!, Left 4 Dead 2 and Garry's Mod
RollerCoaster Tycoon 3: Platinum!
Sid Meier's Railroads!, but funny
Loved · 92%Real-Time with Pause · EconomyAlso like Garry's Mod
SCP: Secret Laboratory
Left 4 Dead 2, but free to play
Loved · 91%FPS · Survival HorrorAlso like Garry's Mod
No More Room in Hell
Left 4 Dead 2, but free to play, and half the hours
Loved · 90%Zombies · SurvivalAlso like Garry's Mod
Ravenfield
Garry's Mod, but single-player, and a third of the hours
Loved · 97%Sandbox · FPSAlso like Left 4 Dead 2
Planet Coaster
Sid Meier's Railroads!, but relaxing, and realistic
Loved · 91%Management · EconomyAlso like Garry's Mod
Railroads Online
Sid Meier's Railroads!, but a driving sim, and three times the hours
Mixed · 75%Trains · EconomyAlso like Garry's Mod
Cities: Skylines
Sid Meier's Railroads!, but single-player, and three times the hours
Loved · 93%Economy · ManagementAlso like Garry's Mod
Call of Duty: World at War
Left 4 Dead 2, but set in World War II
Loved · 92%Zombies · FPSAlso like Garry's Mod
Counter-Strike Nexon
Left 4 Dead 2, but free to play, and PvP
Mixed · 67%Zombies · FPSAlso like Garry's Mod
Blockland
Garry's Mod, but open world, and a quarter of the hours
Mixed · 74%Building · SandboxAlso like Left 4 Dead 2
Zombie Panic! Source
Left 4 Dead 2, but half the hours, and more divisive
Liked · 85%Zombies · FPSAlso like Garry's Mod
Unturned
Left 4 Dead 2, but a survival crafting game
Loved · 91%Zombies · SurvivalAlso like Garry's Mod
Totally Accurate Battlegrounds
Garry's Mod, but free to play, and a battle royale
Liked · 88%Physics · SandboxAlso like Left 4 Dead 2
7 Days to Die
Garry's Mod, but a base builder, and about survival
Liked · 87%Building · SandboxAlso like Left 4 Dead 2
Waterpark Simulator
Garry's Mod, but a management game, and a job sim
Loved · 96%Sandbox · BuildingAlso like Sid Meier's Railroads!
More like Sid Meier's Railroads!
3 games closest to Sid Meier's Railroads! of your picks
Factorio
Sid Meier's Railroads!, but with base building, and nine times the hours
Loved · 98%Trains · Management
Transport Fever 2
Sid Meier's Railroads!, but single-player, and three times the hours
Loved · 90%Trains · Economy
More like Garry's Mod
6 games closest to Garry's Mod of your picks
Scrap Mechanic
Garry's Mod, but a survival crafting game, and with base building
Loved · 92%Building · Physics
Fireworks Mania - An Explosive Simulator
Garry's Mod, but a hobby sim, and a tenth of the hours
Loved · 97%Sandbox · Physics
Hot Dogs, Horseshoes & Hand Grenades
Garry's Mod, but in VR, and half the hours
Loved · 97%Physics · Sandbox
How this list is made
Each game is measured against each of your picks the way a games-like list measures it: the Steam community tags, Steam genres and IGDB themes they share, each counting for more the fewer games carry it. A game's place is how alike it is to your picks together, as a share of each pick's best match, so one alike to two of them comes before one alike to just one. It must be close to at least one of them, as close as it would have to be on that game's own list.
None of your picks is on the list, nor a second release of one, nor a game of their own series. Up to 30 games are shown. Under each name, the kinds it shares with the pick it is closest to, and how it differs from that pick.