Games like Necromantic
Games like Necromantic include Vampire Survivors, Halls of Torment, Hades, Death Must Die, and Brotato. We matched them by the tags players give Necromantic on Steam (Bullet Hell, Hack and Slash, Action Roguelike, Gothic, and Dark Fantasy): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Bullet Hell · Action Roguelike · Singleplayer

Halls of Torment
Shared: Bullet Hell · Action Roguelike · Dark Fantasy

Hades
Shared: Action Roguelike · Hack and Slash · Singleplayer

Death Must Die
Shared: Bullet Hell · Action Roguelike · Hack and Slash

Brotato
Shared: Bullet Hell · Action Roguelike · Singleplayer

Megabonk
Shared: Action Roguelike · Bullet Hell · Roguelike

Soulstone Survivors
Shared: Action Roguelike · Bullet Hell · Hack and Slash

Dead Cells
Shared: Action Roguelike · Roguelike · Hack and Slash

Ravenswatch
Shared: Action Roguelike · Roguelike · Online Co-Op

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

Tower of Babel: Survivors of Chaos
Shared: Bullet Hell · Action Roguelike · Hack and Slash

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

Windblown
Shared: Hack and Slash · Action Roguelike · Online Co-Op

The Spell Brigade
Shared: Bullet Hell · Action Roguelike · Online Co-Op

Noobs Want to Live
Shared: Bullet Hell · Action Roguelike · Roguelike

Hades II
Shared: Hack and Slash · Action Roguelike · Roguelike

Cinderia
Shared: Hack and Slash · Action Roguelike · Roguelike

Alice: Madness Returns
Shared: Dark Fantasy · Hack and Slash · Horror

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

Shape of Dreams
Shared: Action Roguelike · Hack and Slash · PvE

Hero Siege
Shared: Hack and Slash · Action Roguelike · Roguelike

Apocalypse Party
Shared: Action Roguelike · Bullet Hell · Singleplayer

Children of Morta
Shared: Hack and Slash · Action Roguelike · Roguelike

Jotunnslayer: Hordes of Hel
Shared: Action Roguelike · Hack and Slash · Roguelike