Credit to https://www.cats.org.uk/help-and-advice/information-leaflets/veterinary-guides for these amazing guides.
Arthritis 
Diabetes 
Itchy cats and skin disorders 
Feline Parvovirus 
Kidney or renal disease 
Cats with disabilities 
Hypertension 
Feline Immunodeficiency Virus and FeLV 
Feline Coronavirus and FIP 
Heart murmurs and heart disease 
Hyperthyroidism 
Feline asthma 
Teeth and oral health 
Fleas and other parasites 
Cat flu 
Infectious disease and vaccination 
Digestive disorders – vomiting and diarrhoea 
You and your vet 
Cats and pregnant women – Toxoplasmosis