Games like SynthWaves
Games like SynthWaves include Bloons TD 6, Orcs Must Die! 3, Plants vs. Zombies GOTY Edition, Defense Grid: The Awakening, and Emberward. We matched them by the tags players give SynthWaves on Steam (Strategy, Tower Defense, Retro, Futuristic, and Cyberpunk): closest matches first, and among equally close ones the better-known games.

Bloons TD 6
Shared: Strategy · Tower Defense · 3D

Orcs Must Die! 3
Shared: Tower Defense · Strategy · PvE

Plants vs. Zombies GOTY Edition
Shared: Tower Defense · Strategy · Singleplayer

Defense Grid: The Awakening
Shared: Strategy · Tower Defense · Futuristic

Emberward
Shared: Tower Defense · Strategy · 3D

Dota 2
Shared: Strategy · Free to Play · Tower Defense

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

Super Sanctum TD
Shared: Strategy · Tower Defense · Retro

Thronefall
Shared: Strategy · Tower Defense · 3D

Legion TD 2 - Multiplayer Tower Defense
Shared: Tower Defense · Strategy · PvE

Dungeon Defenders
Shared: Tower Defense · Strategy · Singleplayer

Rise to Ruins
Shared: Tower Defense · Strategy · Indie

Rogue Tower
Shared: Strategy · Tower Defense · 3D

Kingdom Rush 5: Alliance TD
Shared: Strategy · Tower Defense · Singleplayer

Kingdom Rush - Tower Defense
Shared: Strategy · Tower Defense · Singleplayer

Rock 'N' Roll Defense
Shared: Strategy · Tower Defense · Indie

Taur
Shared: Strategy · Tower Defense · Indie

Due Process
Shared: Futuristic · 3D · Cyberpunk

Sanctum 2
Shared: Tower Defense · Strategy · Indie

X-Morph: Defense
Shared: Strategy · Tower Defense · Indie

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

GemCraft - Chasing Shadows
Shared: Strategy · Tower Defense · Indie