All API.AI system entities are listed here: https://api.ai/docs/reference/system-entities The values of those entities (which seems to be what you're asking for) are too large to be published (i.e. all cities).
If you wish to add additional entity values I'd recommend creating additional entities (like
tomorrow) with the values you believe should be included (like
abhi) and handle them either in your webhook or with custom responses specifically using those entities in your response in API.AI.
If you haven't already you may want to check if API.AI supports the language you're trying to implement. You can check the language of your agent in your API.AI agent's settings (if is not the right language you can select the language you want when creating a new API.AI agent, a list of support languages is here: https://api.ai/docs/reference/language)