Games like Horde Survivor
Games like Horde Survivor include Vampire Survivors, Halls of Torment, Death Must Die, Brotato, and Megabonk. We matched them by the tags players give Horde Survivor on Steam (Action, Action Roguelike, Bullet Hell, Roguelite, and 2D): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Halls of Torment
Shared: Action Roguelike · Bullet Hell · Roguelite

Death Must Die
Shared: Action Roguelike · Bullet Hell · Roguelite

Brotato
Shared: Bullet Hell · Action Roguelike · Singleplayer

Megabonk
Shared: Action Roguelike · Roguelite · Bullet Hell

20 Minutes Till Dawn
Shared: Action Roguelike · Bullet Hell · Roguelite

Skul: The Hero Slayer
Shared: Action · Action Roguelike · 2D

Hades
Shared: Action Roguelike · Roguelite · Action

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Roguelite · Bullet Hell

Boneraiser Minions
Shared: Action Roguelike · Bullet Hell · Roguelite

BALL x PIT
Shared: Action · Roguelite · Bullet Hell

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Dungreed
Shared: Action Roguelike · Action · Roguelite

Enter the Gungeon
Shared: Action Roguelike · Bullet Hell · Action

Rogue: Genesia
Shared: Action Roguelike · Bullet Hell · Roguelite

Tower of Babel: Survivors of Chaos
Shared: Action Roguelike · Bullet Hell · Roguelite

UnderMine
Shared: Action Roguelike · Roguelite · Action

Nova Drift
Shared: Bullet Hell · Roguelite · Action Roguelike

Nuclear Throne
Shared: Action Roguelike · Action · Bullet Hell

Dead Cells
Shared: Action Roguelike · 2D · Roguelite

Seraph's Last Stand
Shared: Action Roguelike · Bullet Hell · 2D

Noobs Are Coming
Shared: Action Roguelike · Roguelite · Bullet Hell

FatalZone
Shared: Action Roguelike · Bullet Hell · Roguelite

God Of Weapons
Shared: Action Roguelike · Roguelite · Bullet Hell