Games like Upgradia
Games like Upgradia include IdleOn - The Incremental MMO, The Elder Scrolls Online - Standard Edition, Guild Wars 2®, FINAL FANTASY XIV Online, and Neverwinter. We matched them by the tags players give Upgradia on Steam (Idler, Adventure, RPG, Simulation, and MMORPG): closest matches first, and among equally close ones the better-known games.

IdleOn - The Incremental MMO
Shared: Idler · MMORPG · RPG

The Elder Scrolls Online - Standard Edition
Shared: RPG · Adventure · MMORPG

Guild Wars 2®
Shared: Adventure · MMORPG · RPG

FINAL FANTASY XIV Online
Shared: RPG · MMORPG · Adventure

Neverwinter
Shared: RPG · Adventure · MMORPG

Pantheon: Rise of the Fallen
Shared: Adventure · RPG · MMORPG

Melvor Idle
Shared: Idler · RPG · Adventure

Albion Online
Shared: MMORPG · RPG · PvP

The Quinfall
Shared: RPG · MMORPG · Adventure

Shop Titans
Shared: Idler · RPG · Simulation

Firestone – Idle Clicker Online RPG
Shared: Idler · Incremental · RPG

Dragon Cliff
Shared: Idler · RPG · Adventure

Gloria Victis: Medieval MMORPG
Shared: MMORPG · RPG · Simulation

Heroes of Might and Magic: Olden Era
Shared: RPG · Turn-Based Strategy · Simulation

Dark and Light
Shared: RPG · Adventure · MMORPG

Black Desert
Shared: MMORPG · PvP · Adventure

Idle Champions of the Forgotten Realms
Shared: Idler · Adventure · Incremental

Rust
Shared: Adventure · PvP · Crafting

Pax Dei
Shared: MMORPG · RPG · PvP

Temtem
Shared: RPG · Adventure · PvP

Last Oasis
Shared: RPG · Adventure · Massively Multiplayer

Mewgenics
Shared: RPG · Turn-Based Strategy · Turn-Based Tactics

Graveyard Keeper
Shared: RPG · Simulation · Adventure

Mortal Online 2
Shared: MMORPG · RPG · PvP