Various food wastes. Food is eaten in every country.
Also: hair, fur, feathers, cloth, and dead bugs.

"ps: no starbucks in Uruguay, so no coffee grounds either"

Are there other coffee houses near you? Or restaurants? If so, ask if they'd save the grounds for you. Let them know how you plan to use them and offer to bring a bucket to save them. Use two buckets, so you can drop one off (clean) when you pick the full one up.

Are there grocery stores or markets nearby where you could ask the merchants for their leftover spoiled fruit/vegetables that they would otherwise throw away?
I think that with the manure and dried leaves, you would have a good start on stuff to do lasagna-style layering over newspaper or cardboard right on your planting beds...tuck in some greens and keep it moist and it will all break down.

Are you near the ocean, or a fish stand or fish market? Lots of people use fish waste. It's a strong green. Some people use seaweed, if you can get any of that?

And I second the idea of spoiled produce from the grocery store.

Chicken manures and rabbit manures, etc, other livestock manures, are possibilities.

Peoples thoughts on Coffee grounds are often way over blown. As part of a total mixture of organic matter they are all right but they should not be the only organic matter added to your soil.
So Santi what is available to you? Any once living vegetable waste material can be used. The left over waste from preparing vegetables for eating, any deciduous tree leaves, if possible planting something in the garden just for more OM (although that is often too expensive for many gardeners to do). Look around to see what vegetative waste is available to you.

thanks for all the replies. Tas123 i can't ask for materials to compost because, me space is very limited and my compost bin could be seen as a small bucket, which can only hold my own waste, and i get very little amounts of compost from it, and the raised beds are already laid out.

What i meant was, what accsesible OM can i get to apply directly to the soil, as mulch and/or soil enhancer?

I think most of the original suggestions still apply. I think I'd be a little wary of applying fish waste to the surface, but you could bury it. I would probably bury it either at the very beginning of the growing season (just before planting) or at the end of the growing season. You would want to bury it deeply enough that it won't attract animals.

Coffee grounds and vegetable waste from restaurants and grocery stores would be good sources of greens. Tree leaves, shredded paper, cardboard, chipped wood, sawdust are all examples of browns. If you're putting this on a garden or flower bed, you could just do it in layers.

Yes, I didn't mean to start composting in a bin...I meant that you could layer the materials onto your garden area and they would eventually break down. Especially the leaves and manure. I'm sure that there is an article somewhere on these forums about lasagna gardening - I couldn't find it quickly, does anyone else have time to find it an post a link?

If you google "compost ingredients" you will find many different lists of things to use for composting. Any of these can also be used right into a bed, skipping the compost bin completely.

Also try googling "lasagna gardening" as tas123 suggested, or "interbay mulch". I've done this several times, and the results are great. You can layer whatever you have available- manure, kitchen scraps, yard waste, chipped wood, etc. Leaves and grass clippings are my favorites. Even if you don't have a huge amount at once, you can add materials as they become available.

Karen