Games like ball.io
Games like ball.io include Last Oasis, Tower Unite, SMITE 2, Infestation: The New Beginning, and Rust. We matched them by the tags players give ball.io on Steam (Massively Multiplayer, Casual, Indie, MOBA, and Multiplayer): closest matches first, and among equally close ones the better-known games.

Last Oasis
Shared: Massively Multiplayer · Action · Indie

Tower Unite
Shared: Casual · Massively Multiplayer · Multiplayer

SMITE 2
Shared: MOBA · Action · Casual

Infestation: The New Beginning
Shared: Massively Multiplayer · Action · Multiplayer

Rust
Shared: Multiplayer · Open World · Massively Multiplayer

ShellShock Live
Shared: Multiplayer · Casual · Action

Notes of Soul
Shared: Massively Multiplayer · Action · Indie

SMITE®
Shared: MOBA · Multiplayer · Action

Dota 2
Shared: MOBA · Multiplayer · Action

Where Winds Meet
Shared: Multiplayer · Open World · Massively Multiplayer

Outlaws of the Old West
Shared: Massively Multiplayer · Multiplayer · Indie

The Elder Scrolls Online - Standard Edition
Shared: Massively Multiplayer · Multiplayer · RPG

Touhou Big Big Battle
Shared: Massively Multiplayer · Indie · Casual

Gloria Victis: Medieval MMORPG
Shared: Massively Multiplayer · Action · Open World

Town of Salem
Shared: Multiplayer · Indie · Casual

VRChat
Shared: Multiplayer · Massively Multiplayer · Casual

BidKing
Shared: Casual · Massively Multiplayer · MOBA

Vampire Survivors
Shared: Bullet Hell · Indie · Casual

Once Human
Shared: Multiplayer · Open World · Action

Tom Clancy’s The Division™
Shared: Multiplayer · Open World · Action

Mount & Blade II: Bannerlord
Shared: Multiplayer · Open World · RPG

The Isle
Shared: Multiplayer · Massively Multiplayer · Open World

EmergeNYC
Shared: Multiplayer · Action · Open World

ArcheBlade™
Shared: Massively Multiplayer · Action · Multiplayer