Games like Idle Hero TD - Tower Defense RPG
Idle Hero TD - Tower Defense RPG leans idle, never really ends. These games share the most with it, and each one says why.

Summoners Greed: AFK TD TowerUpdated
Also tower defense, auto battler, rpg · Same active/idle balance (leans idle)
Summon heroes, place them on a grid to hold off waves, and collect rewards that build up while the game is closed.
75% idle
Idling to Rule the Gods
Also rpg · Same active/idle balance (leans idle)
Train clones, fight gods, rebirth. An old-school Unity idler that still has a loyal crowd.
85% steam75% idle
Legend of Slime: Idle RPGUpdated
Also rpg, auto battler · Same active/idle balance (leans idle)
Lead a clan of slimes through automatic battles, evolving heroes and gathering loot even while offline.
75% idle
Rogue with the Dead: Idle RPGUpdated
Also rpg, tower defense · Same active/idle balance (leans idle)
March an army 300 miles to slay the Demon Lord; troops fight automatically, and each death resets your run but makes you stronger.
has ending75% idle
Desktop Defender
Also auto battler, tower defense
A lone tower in the corner of your screen holds off waves while you work, dropping gear to equip and resetting runs for permanent ascension upgrades.
92% steam90% idle
Bloobs Adventure Idle
Also rpg · Same active/idle balance (leans idle)
A RuneScape-style idle RPG with 24 linked skills, automated boss fights, soul collecting and skill prestige, plus banked offline time to spend later.
88% steam75% idle
Melvor Idle
Also rpg · Same active/idle balance (mostly idle)
RuneScape's skilling loop distilled into menus. Train twenty skills, fight dungeons, fill the completion log.
90% steam85% idle
Legends of IdleOn
Also rpg · Same active/idle balance (mostly idle)
An idle MMO with a whole account of characters working different skills at once. Massive, sprawling, social.
77% steam80% idle
Firestone Idle RPG
Also rpg · Same active/idle balance (mostly idle)
A big, polished free-to-play hero idler with guilds, expeditions and a lot of timers.
77% steam80% idle
Incremental Epic Hero 2
Also rpg, auto battler
Six heroes battle automatically across a fantasy world while you upgrade nearly everything and juggle many prestige systems, with over 1,000 hours of content.
72% steam
NGU Idle
Also rpg · Same active/idle balance (leans idle)
Joke-dense RPG idler with dozens of interlocking systems. Beating a boss is the easy part; allocating energy is the game.
96% steam65% idle
Evitania Online - Idle RPG
Also rpg · Same active/idle balance (leans idle)
An online idle RPG with classes and talent trees where your character fights and gathers while offline, and alts can level mining and woodcutting.
78% steam75% idle
Idle Monster TD: Evolved
Also tower defense · Same active/idle balance (leans idle)
A reverse tower defense where you evolve over 150 monsters to hold a portal against endless human invaders, placing them to combine abilities.
76% steam75% idle
Clicker Heroes
Also rpg
Click monsters, hire heroes, ascend, transcend. The game that made idle RPGs mainstream on Steam.
90% steam60% idle
Endless Frontier - RPGUpdated
Also rpg · Same active/idle balance (leans idle)
Lead a squad of knights and mages up thousands of stages against titans and dragons, with units that keep climbing and leveling on their own while you are away.
75% idle
Legends of Monster:Idle RPGDormant
Also rpg · Same active/idle balance (leans idle)
Start as a baby dinosaur and grow into a giant city-smashing monster, upgrading stats through auto battles that continue while you are logged off.
75% idle
Slayer LegendUpdated
Also rpg · Same active/idle balance (leans idle)
Raise a pixel-art demon slayer through AFK combat, leveling gear and combining elemental skills in a retro fantasy world.
75% idle
Legends of Dragaea: Idle DungeonsUpdated
Also rpg, auto battler
A first-person idle dungeon crawler where parties from nine races explore dungeons, take on 9-hero raids and grow your own guild and town.
86% steam
Lootborne
Also rpg, auto battler
A dark fantasy auto-battler that runs in a small desktop window, with a hero fighting and looting on its own. Forge duplicates, stack elemental synergies and battle other builds in async PvP.
61% steam90% idle
Idle Champions of the Forgotten Realms
Also rpg
Dungeons & Dragons formation-building idler. Heavy on events and collection.
77% steam60% idle
Idle Monster TD
Also tower defense · Same active/idle balance (leans idle)
Place elemental monsters on the map to hold off endless robot waves, combining their abilities and upgrading stats between fights.
72% steam70% idle
Loot LoopUpdated
Also rpg, auto battler
Send a party of tiny heroes into dungeon runs that last seconds, then spend the loot on a large skill tree between attempts.
92% steam
The Perfect Tower II
Also tower defense
Tower defence as an idle engine, plus factories, mining and an in-game scripting language.
87% steam60% idle
SkelesellerUpdated
Also rpg, auto battler
A dead adventurer returns as a skeleton shopkeeper who hires heroes, sends them into battle and sells their loot to grow the town. Finite, with small numbers and no prestige.
91% steamhas ending