Games like TransmuTowers
Games like TransmuTowers include Bloons TD 6, Dungeon Defenders, Orcs Must Die! 3, Bloons TD 5, and Thronefall. We matched them by the tags players give TransmuTowers on Steam (Tower Defense, Strategy, Online Co-Op, Co-op Campaign, and Strategy RPG): closest matches first, and among equally close ones the better-known games.

Bloons TD 6
Shared: Tower Defense · Strategy · Online Co-Op

Dungeon Defenders
Shared: Tower Defense · Online Co-Op · Strategy

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

Bloons TD 5
Shared: Tower Defense · Strategy · Action

Thronefall
Shared: Tower Defense · Strategy · Action

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

Orcs Must Die! 2
Shared: Tower Defense · Strategy · Online Co-Op

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

The Riftbreaker
Shared: Online Co-Op · Tower Defense · Action

Kingdom Rush Frontiers - Tower Defense
Shared: Tower Defense · Strategy · Casual

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

Sanctum 2
Shared: Tower Defense · Strategy · Online Co-Op

Orcs Must Die!
Shared: Tower Defense · Strategy · Action

Witch It
Shared: Online Co-Op · Casual · Funny

Kingdom Rush Origins - Tower Defense
Shared: Tower Defense · Strategy · Casual

Mindustry
Shared: Tower Defense · Strategy · Online Co-Op

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

Who's Your Daddy?!
Shared: Online Co-Op · Strategy · Funny

ShellShock Live
Shared: Strategy · Action · Online Co-Op

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

Legion TD 2 - Multiplayer Tower Defense
Shared: Tower Defense · Strategy · Online Co-Op

Dungeon Defenders: Awakened
Shared: Online Co-Op · Tower Defense · Strategy

Orcs Must Die! Deathtrap
Shared: Tower Defense · Strategy · Action

Embr
Shared: Strategy · Action · Co-op Campaign