Games like Sylph
Games like Sylph include Elite Dangerous, X4: Foundations, SpaceEngine, Universe Sandbox, and X-Plane 11. We matched them by the tags players give Sylph on Steam (Flight, Realistic, Simulation, Space Sim, and Sci-fi): closest matches first, and among equally close ones the better-known games.

Elite Dangerous
Shared: Space Sim · Space · Simulation

X4: Foundations
Shared: Simulation · Space · Space Sim

SpaceEngine
Shared: Sci-fi · Space Sim · Realistic

Universe Sandbox
Shared: Simulation · Space Sim · Realistic

X-Plane 11
Shared: Flight · Simulation · Realistic

Microsoft Flight Simulator (2020) 40th Anniversary Edition
Shared: Flight · Simulation · Realistic

Kerbal Space Program
Shared: Simulation · Space · Space Sim

Uncrashed : FPV Drone Simulator
Shared: Flight · Simulation · Realistic

No Man's Sky
Shared: Space · Sci-fi · Exploration

Reentry - A Space Flight Simulator
Shared: Flight · Simulation · Realistic

Kerbal Space Program 2
Shared: Space · Exploration · Simulation

Flight Of Nova
Shared: Flight · Simulation · Space Sim

Microsoft Flight Simulator 2024
Shared: Flight · Simulation · Realistic

Hardspace: Shipbreaker
Shared: Simulation · Sci-fi · Space

X-Plane 12
Shared: Flight · Simulation · Realistic

Starfield
Shared: Space · Sci-fi · Exploration

Avorion
Shared: Space Sim · Flight · Exploration

Exo One
Shared: Flight · Space · Exploration

Liftoff®: FPV Drone Racing
Shared: Flight · Simulation · Realistic

Microsoft Flight Simulator X: Steam Edition
Shared: Flight · Realistic · Simulation

Euro Truck Simulator 2
Shared: Simulation · Realistic · Exploration

V: Rings of Saturn
Shared: Sci-fi · Space · Space Sim

BeamNG.drive
Shared: Simulation · Realistic · Physics

STAR WARS™: Squadrons
Shared: Flight · Space · Sci-fi