Games like One Drop
Games like One Drop include Celeste, Super Meat Boy, Geometry Dash, Downwell, and Jump King. We matched them by the tags players give One Drop on Steam (Precision Platformer, 2D Platformer, Collectathon, Parkour, and Difficult): closest matches first, and among equally close ones the better-known games.

Celeste
Shared: Precision Platformer · Difficult · 2D Platformer

Super Meat Boy
Shared: Precision Platformer · 2D Platformer · Difficult

Geometry Dash
Shared: Difficult · Precision Platformer · 2D

Downwell
Shared: Precision Platformer · 2D Platformer · Platformer

Jump King
Shared: Precision Platformer · Difficult · Psychological Horror

SANABI
Shared: 2D Platformer · 2D · Platformer

I wanna be the Creator
Shared: Platformer · Precision Platformer · Difficult

VVVVVV
Shared: Precision Platformer · 2D Platformer · Platformer

Hollow Knight
Shared: Platformer · Difficult · 2D

Pogostuck: Rage With Your Friends
Shared: Precision Platformer · Difficult · Platformer

Rogue Legacy 2
Shared: Arcade · Platformer · Difficult

Nine Sols
Shared: Difficult · Platformer · 2D

Hollow Knight: Silksong
Shared: Difficult · Platformer · 2D

N++ (NPLUSPLUS)
Shared: Precision Platformer · 2D Platformer · Difficult

A Difficult Game About Climbing
Shared: Difficult · Precision Platformer · Platformer

The End Is Nigh
Shared: Precision Platformer · Platformer · Difficult

Rain World
Shared: Difficult · Platformer · 2D Platformer

Thomas Was Alone
Shared: 2D Platformer · Precision Platformer · Platformer

Symphonia
Shared: Precision Platformer · Difficult · 2D Platformer

Spelunky 2
Shared: 2D Platformer · Platformer · Difficult

Cuphead
Shared: Difficult · Platformer · 2D

Pepper Grinder
Shared: 2D Platformer · Difficult · Platformer

Ambidextro
Shared: Precision Platformer · 2D Platformer · Platformer

Super Meat Boy Forever
Shared: Precision Platformer · Difficult · Platformer