Slowking

A habitat matching this ambience raises Comfy Level faster. Time and weather gate whether a Pokémon turns up at a habitat at all — though light overrides the clock: a night Pokémon spawns at any hour if its habitat sits somewhere dark such as a cave or underground, and a day Pokémon spawns at night if its habitat is ringed with light.

Give or place anything matching these and both friendship and Comfy Level rise much faster — a matching item lays down with a bigger sparkle. For a Pokémon with the Trade specialty, matching items are also worth 50% more on the scale.

1 Lots of water

30+ items

Resort hammockTable settingPaper Party cupsSoda floatShaved iceModern sinkToiletSinkBathtime setCleaning suppliesShowerBathtubBouncy blue bathtubHumidifierFunky diffuserWater basinCanoeInflatable boatBeach parasolHorsea fountainFire hydrantSprinklerMystic WaterWater pillar quarterHoppip water bottleJuice trioTeaware setBottled shipGyarados fountainBubble machine

2 Cleanliness

14+ items

Waterproof seatLarge mirrorModern sinkWashing machineToiletSinkTowel rackBathtime setCleaning suppliesShowerBathtubBouncy blue bathtubWater basinCooler

3 Strange stuff

120+ items

Armor fragmentPolygonal ShelfWall mirrorLarge mirrorLuxury dresserCute dresserWiggly mirrorPitcher-plant potModern sinkCooking stoveMicrowave ovenRefrigeratorAir conditionerPrinterWashing machineToiletSinkShowerBathtubBouncy blue bathtubTabletCell phoneLaptopComputerGaming PCAlarm ClockHumidifierFunky diffuserCrystal ballMicroscopeStanding micCool electric guitarCool bass guitarAudio mixerGold TeethRepelPunching gameBoo-in-the-boxWobbuffet WobblerAuspicious ArmorMalicious ArmorClear BellTidal BellMysterious statueFiery Magby statueSpacesuitModel space shuttleSpaceshipDecorative storage shelfRowlet clockHanging scrollCeiling fanCastform weather charmGrubby tabletGrubby cell phoneBikeGravestoneCannonBellSmall stageHorsea fountainSignpostInformation boardFire hydrantExcavation toolsLarge ventilation fanCash registerSprinklerMini generatorCard readerPoké Ball lampModel planetMusic mat (low do)Music mat (Re)Music mat (Mi)Music mat (Fa)Music mat (Sol)Music mat (La)Music mat (Ti)Music mat (High do)Large Lost RelicSmall Lost RelicTwisted SpoonTown mapTeam Rocket Wall HangingSkull FossilArmor FossilJaw FossilSail FossilWing Fossil (head)Wing Fossil (right wing)Wing Fossil (left wing)Wing fossil (body)Wing Fossil (tail)Headbutt Fossil (head)Headbutt Fossil (body)Headbutt Fossil (tail)Shield Fossil (Head)Shield Fossil (body)Shield Fossil (tail)Despot Fossil (head)Despot Fossil (body)Despot Fossil (legs)Despot Fossil (tail)Tundra Fossil (head)Tundra Fossil (body)Tundra Fossil (tail)Inflatable SudowoodoDigital cameraStar-shaped DresserTelescopeCloud cannonMarine dresserMetronomeMusic boxServersParty ballGyarados fountainBubble machineCursola light

4 Group activities

5 Healing

4+ items

HumidifierFirst aid kitThroat SprayShop shelf

Flavour: sour

8 foods

Aspear BerryTomatoShredded saladFlavorful soupLeppa breadTomato hamburger steakSoda PopRefreshing soda smoothie

Two caveats. The game lists these five in a fixed order, but no source says the first counts for more than the fifth — the numbers are the in-game order, not a strength ranking. And the item lists are incomplete: Serebii marks them as still being filled in, so each count is a floor, not a total.