Well since i see no interest on making a good answer and finally i got plenty of time to get to it here is my answer, i will clasify them on 7 categories from most dificult to less dificult
1: -- Because they are strong creature that run away and need high level team to kill them
Capricious Phantom
Distorted Phantom
Infernal Phantom
Mould Phantom
Vibrant Phantom
2: -- Because they are strong creature that need high level team to kill them
Brachiodemon
Many Faces
Infernal Demon
Bony Sea Devil
Turbulent Elemental
Courage Leech
Cloak of Terror
Knight's Apparition
Paladin's Apparition
Sorcerer's Apparition
Druid's Apparition
Branchy Crawler
Rotten Golem
3:-- Because of their super rare spawn
Yeti
Midnight Panther
Crustacea Gigantica
Dire Penguin
4: -- Because there are not many to kill and need to wait for them to respawn (Time required to complete is really high)
Filth Toad (every 20 minutes apears one or something like that)
Infernalist
Warlock
Lost Exile
Gryphon
Mole
Dragonling
Infected Weeper
Nomad (blue)
5: -- Because they need to be done in team due the high hp and debuff they give
Terrorsleep
Feversleep
Sight of Surrender (to do them fast you need a team of at least 5 with 2 eds level 300 average and open their cave on roshamuul by doing the task of the butterfly)
6: -- Because they run away and hit hard but can be done in team after few hunts
True Frost Flower Asura
Cursed Prospector
Evil Prospector
7:-- Because you need to live with what you have done
Cat
Dog
Husky
Source: Own Experience and https://tibiadraptor.com/bestiary
Image due poor quality: https://imgur.com/a/KTT6vzp
if there are any sugestion i will glady make and update