Is there a list on here with visa requirements (tourist) for various countries such as

Cambodia

Vietnam

Malaysia

Laos

Did a search but no one stop shop post which would be usefull for me and others I guess!!

Don't know of a list but;

Cambodia - On arrival or on-line in advance

Vietnam - In advance only, from embassy/consulate or online via agent (air entry only)

Malaysia - Most (EU, USA, AUS) can get waiver entry on arrival

Laos - In advance or on arrival, not sure about online.

None have any kind of onerous entry requirements, photos, fill in forms, pay $, you're in.

No such list exists, as far as I know. There are lists where you can check if a visa is required (IATA data-base is pretty good), but not what the requirements for a visa are.