Games like Idle Pocket Planet
Idle Pocket Planet. These games share the most with it, and each one says why.

TerraGenesis - Space SettlersUpdated
Also idle, planet, space
Terraform real and fictional planets using NASA data, building habitats and choosing among four factions.

Battle Royale Tycoon Idle GameDormant
Also merge, idle, collection
Slide and merge weapon tiles on a grid to build a battle royale arsenal of hundreds of weapons.

Mega Tower - Casual TD GameUpdated
Also merge, idle, space
Merge and modify towers in a sci-fi tower defense that fights on its own but lets you aim manually.
50% idle
Idle Animal EvolutionDormant
Also idle, collection, merge
Breed hybrid creatures in a lab by crossing pairs of animals.

Merge Plane Tycoon: Idle GamesDormant
Also merge, idle, collection
Buy and merge planes into new models, managing parking and flight tracks so they earn money even while you are offline.
75% idle
Cast n Chill
Also collection, idle
A relaxed pixel fishing game with a dog companion where you sell catches for better gear across 16 spots, and can switch to a passive mode that fishes for you.
95% steam50% idle
Fish to Dish: Idle Sushi
Also collection, idle
A fishing boat sits along the edge of your desktop reeling in sea life to serve as sushi, while you upgrade rods and bait and fill an aquarium.
96% steam90% idle
To The Core
Also space, planet
Fly between planets, drill for resources until fuel runs out, and buy upgrades so each dig reaches deeper than the last.
93% steam
Fruit Stand Fortune
Also idle, collection
Spin slot machines and pachinko boards for fruit to sell at Kate the Cat's stand, unlocking odd customers and auto-click upgrades.
96% steam
Bugtopia
Also idle, collection
Raise and breed over 300 real-world insect species in terrariums you landscape yourself, with breeding boxes that can produce rare new bugs.
92% steam
Idle Waters
Also collection, idle
Fish from a window at the bottom of your screen, manually or with auto-fishing, to fill a collection of 100 species across 12 biomes and stock your aquarium.
94% steam90% idle
Angel Legion
Also collection, space
A 3D hero-collection RPG where resources build up automatically. Recruit and dress a roster of angels across three warring space factions.
85% steam70% idle
Space industrial empire
Also space, planet
Lay out flat conveyor lines for mining, smelting and research, then build warships to take other planets.
87% steam70% idle
Holoidle
Also collection, idle
Grow a Hololive streamer's influence with upgrades and a deck of collectible collab cards, placing up to six for synergy bonuses.
84% steam
Gear clickerDormant
Also idle, merge
Buy, merge and place gears to build a factory, working through levels with their own challenges.

Hooked Inc: Fishing GamesUpdated
Also collection, idle
Swipe to catch fish, hire a crew that keeps fishing when you're away, and upgrade boats to reach new waters.
50% idle
AFK ArenaUpdated
Also collection, idle
A hero-collecting idle RPG with a campaign, a beast system and co-op modes.

Pocket Champs PVP Racing GamesUpdated
Also idle, collection
Train a small champion in running, flying and climbing, equip gadgets, then race other players online.

Merge and DigUpdated
Also merge, idle
Merge pickaxes into stronger ones and drop them onto blocks to mine resources, with rewards building while you're away.
75% idle
Idle MafiaUpdated
Also collection, idle
Run criminal businesses, collect capos with special abilities and take over territory while your crew does the work.
75% idle
Train Miner: Idle Railway GameUpdated
Also merge, idle
Chop trees for materials, merge carriages and lay track to expand a train empire.

Invincible: Guarding the GlobeUpdated
Also collection, idle
Recruit characters from Invincible, merge clones to rank them up, and run idle battles in the background.
75% idle
Dessert Factory IdleUpdated
Also idle, merge
Bake treats in a dessert factory and combine matching machines to upgrade them into ones that make fancier sweets.

Mythic Heroes: Idle RPGUpdated
Also idle, collection
Summon gods and heroes from many mythologies into a party that battles on its own or under your direction.