Games like Starfend
Games like Starfend include Megabonk, Rogue: Genesia, Soulstone Survivors, Hades, and Age of Darkness: Final Stand. We matched them by the tags players give Starfend on Steam (Tower Defense, Action Roguelike, Hero Shooter, Action RTS, and Bullet Heaven): closest matches first, and among equally close ones the better-known games.

Megabonk
Shared: Action Roguelike · Bullet Heaven · Roguelite

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

Soulstone Survivors
Shared: Action Roguelike · Bullet Heaven · Roguelite

Hades
Shared: Action Roguelike · Roguelite · Roguelike

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

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

Astro Prospector
Shared: Action Roguelike · Incremental · Roguelite

Necrosmith
Shared: Action Roguelike · Tower Defense · Roguelite

Vampire Survivors
Shared: Action Roguelike · Roguelite · Roguelike

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

Nordic Ashes: Survivors of Ragnarok
Shared: Action Roguelike · Bullet Heaven · Roguelite

Yet Another Zombie Survivors
Shared: Action Roguelike · Bullet Heaven · Roguelite

Brotato
Shared: Action Roguelike · Bullet Heaven · Roguelike

The Spell Brigade
Shared: Bullet Heaven · Action Roguelike · Roguelite

Halls of Torment
Shared: Action Roguelike · Roguelite · Roguelike

Sir, We Have an Orc Problem
Shared: Tower Defense · Incremental · Roguelite

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

EverSiege: Untold Ages
Shared: Action RTS · Tower Defense · Roguelite

Tower Dominion
Shared: Tower Defense · Roguelite · RTS

Risk of Rain 2
Shared: Action Roguelike · Roguelite · Roguelike

Hades II
Shared: Action Roguelike · Roguelite · Roguelike

Skul: The Hero Slayer
Shared: Action Roguelike · Roguelite · Roguelike

Jotunnslayer: Hordes of Hel
Shared: Action Roguelike · Bullet Heaven · Roguelite

Bad North: Jotunn Edition
Shared: Tower Defense · Action Roguelike · RTS