Games like Summon Stone
Games like Summon Stone include Plants vs. Zombies GOTY Edition, Bloons TD 6, Zup! S, Progressbar95, and Pikuniku. We matched them by the tags players give Summon Stone on Steam (Casual, Puzzle, Tower Defense, Real Time Tactics, and 2D): closest matches first, and among equally close ones the better-known games.

Plants vs. Zombies GOTY Edition
Shared: Tower Defense · Casual · 2D

Bloons TD 6
Shared: Tower Defense · Casual · Multiplayer

Zup! S
Shared: Casual · Puzzle · 2D

Progressbar95
Shared: Casual · Puzzle · Tower Defense

Pikuniku
Shared: Casual · Puzzle · Indie

Liars Bar
Shared: Casual · PvP · Multiplayer

Peggle Deluxe
Shared: Casual · Puzzle · 2D

Zup! F
Shared: Casual · Puzzle · 2D

Zup!
Shared: Casual · Puzzle · 2D

Zup! 2
Shared: Casual · Puzzle · 2D

Draw & Guess
Shared: Casual · 2D · Multiplayer

Zup! X
Shared: Casual · Puzzle · 2D

Gorogoa
Shared: Puzzle · Casual · Indie

Zup! 3
Shared: Casual · Puzzle · 2D

There Is No Game: Wrong Dimension
Shared: Puzzle · Casual · Indie

Kingdom Rush - Tower Defense
Shared: Tower Defense · Casual · 2D

Legion TD 2 - Multiplayer Tower Defense
Shared: Tower Defense · PvP · Multiplayer

Zup! 8
Shared: Casual · Puzzle · 2D

Hexcells
Shared: Casual · Puzzle · Indie

World of Goo
Shared: Puzzle · Casual · 2D

Hook
Shared: Casual · Puzzle · 2D

Yokai Art: Night Parade of One Hundred Demons
Shared: Tower Defense · Casual · Real Time Tactics

Defend Your Life: TD
Shared: Casual · Tower Defense · 2D