Games like Biletide
Games like Biletide include They Are Billions, Stronghold: Definitive Edition, Stronghold Crusader: Definitive Edition, Stronghold HD (2012), and Age of Darkness: Final Stand. We matched them by the tags players give Biletide on Steam (Strategy, Tower Defense, RTS, Real Time Tactics, and Base Building): closest matches first, and among equally close ones the better-known games.

They Are Billions
Shared: Strategy · Base Building · RTS

Stronghold: Definitive Edition
Shared: Strategy · Real Time Tactics · RTS

Stronghold Crusader: Definitive Edition
Shared: Strategy · Real Time Tactics · Tower Defense

Stronghold HD (2012)
Shared: Real Time Tactics · Tower Defense · Building

Age of Darkness: Final Stand
Shared: Tower Defense · Strategy · RTS

Mindustry
Shared: Tower Defense · Base Building · Strategy

Planetary Annihilation: TITANS
Shared: Strategy · RTS · Real Time Tactics

Creeper World 4
Shared: Tower Defense · Real Time Tactics · RTS

Going Medieval
Shared: Strategy · Base Building · Survival

The Riftbreaker
Shared: Tower Defense · Base Building · Survival

Tower Dominion
Shared: Strategy · Tower Defense · RTS

DG2: Defense Grid 2
Shared: Strategy · Tower Defense · RTS

Kingdom Two Crowns
Shared: Tower Defense · Strategy · Base Building

Frostpunk
Shared: Strategy · Survival · Building

Aliens: Dark Descent
Shared: Strategy · RTS · Real Time Tactics

Creeper World 3: Arc Eternal
Shared: Strategy · Tower Defense · RTS

Manor Lords
Shared: Strategy · Base Building · Building

Thronefall
Shared: Strategy · Tower Defense · Base Building

Cartel Tycoon
Shared: RTS · Strategy · Building

Stronghold Crusader HD (2012)
Shared: Real Time Tactics · Strategy · Building

Farthest Frontier
Shared: Strategy · Building · Economy

Taur
Shared: Strategy · Tower Defense · Base Building

RimWorld
Shared: Strategy · Base Building · Survival

Age of Mythology: Retold
Shared: Strategy · RTS · Base Building