What may aliens want from us?

For decades people have been wondering: if aliens exist what could they want from us.
I wanted to investigate in this topic and I have found some interesting things to say. The things I will talk about have some good arguments in favor that could explain why aliens would want to visit us.
So I will make a list of the most possible things:

Slavery

The possibility of aliens not be friendly is high, why would they care about us, maybe for them and their culture (extremely different to ours) killing and colonizing is not a bad thing, so they would colonize other planets with the simple objective of making them rich, the same as the great powers did during the imperialism.

As you would imagine, if aliens suddenly arrived to our planet, it would mean they have an extraordinary technology much better then ours and second they would use some countries giving them technology in exchange of doing wars all over the earth.

It is not such a crazy idea that they would want to work for them as slaves, because unlike other animals or machines we have the hability to think by ourselfs and obey complex orders, also they would want us to give them some ideas to improve our productivity and maybe even improve their technology by seeing ours and discovering new things.

Earth resources

As you know the earth is rich in lots of materials and elements that are difficult to be found in other places, the most of them have already been taken for humans and used for our purposes, but what if aliens needed for example water because they have run of in their, I know that with technology it wouldn't be difficult for them to create water, but just to explain it, don't you think they would take ours without asking?

This possiblity is kind of related to the slavery one, because they might use us as slaves to extract the resources, but also they could kill all of us and taking the resources by they own because they would do it much faster. Both option could happen but I think the second is more probable.

They would only take earth resources for their purposes, so they could create more objects and things that helped them improve as a civilization (if we say a civilization is better for having a better technology).
After doing that they could leave the earth and let us be free, kill us because they don't want to risk themselves by our revenge or colonizing the planet so they have more places to live.

Just meet us and trade

I think this is the option with less possiblities but it's also possible, maybe their civilisation is against war and in favour of trading of any type, if they met us with the objective of learning and trading both civilisations would improve and have a much better knowledge of everything.

Some of the things they might want are our technology, we give them ours and vice versa, so both would speed up their technology progress for years, maybe even decades or centuries, other things they could want are manufactured products, but we should establish some kind of relation with their money and ours so trading makes sense, or instead of that we could do barters as humans did in the past.

In conclusion, this would be the best option for everyone but it would take more years to happen so aliens should choose between fast and high winning of resourses or slow but high wining in resources, technology culture and other things important for a society.

So which one do you think is more probable, and why?