Here is a list of the wide variety of Monsters that feature in EscapeRuins. Each page will give details about that monster, including their drops and locations. The list is in order of Combat Level:
Cow/Cow calf - Level 2
Giant rat - Level 3/6
Crawling Hand - Level 7/8/11/12
Rock crab - Level 13
Evil Chicken - Level 19
Guard - Level 22
Skeleton - Level 22/25
Banshee - Level 23
Zombie - Level 49/79/120
Infernal Mage - Level 66
Bloodveld - Level 76
Gargoyle - Level 111
Aberrant specter - Level 96
Giant Mole - Level 230
General Graardor - Level 624