I recently did a April Fools thread covering this topic, but it would be good to repeat it in a more serious tone.

Portuguese upon their arrival around 1500 evaluated the trade going on and decided the best items to sell were metals of which most important was copper, but also alumstone, tin, lead. Coins of gold and silver were also massively brought, but it seems in value and volume copper was dominating. Additionally, there were small scale attempts to import textiles, and even more dyes for textiles. Corals were also very popular and valuable.

Most of those items were nothing revolutionary, mostly it was products from Europe that were anyway reaching to the East through Venetian-Egypt trasnfer route which dominated the East-West trade before the rounding of Africa

Here are some tables I have on hand of various ships cargos of Portuguese in the early 16th century. The tables are screenshot from K.S. Mathews Commodity composition of the Indo-Portuguse trade in the early sixteenth century

It is worth note that as Portuguese were bringing massive amounts of spices back, and sending comparatively little in weight products east, a lot of their ships were carrying supplies, mostly military and weapons for their Empire there. There was a massive need for Crown to send supplies to the East.

The ships were additionally overcrowded with people, large part soldiers sent officially on three year mandates to the East, some just emigrants who had to pay for their way there. by the end of 16th century this dropped as more people were emigrating to Brazil, which was also a safer and shorter voyage and by that time established itself as a safer and more lucrative destination

In addition to the Portuguese trade, we have information on what did Magellan's ship carry in their attempt to reach the Spice islands by western route. Despite his mission being exploratory (and as such had less commercial nature) they brought along large numbers of items to trade with natives, some for South America some for when they reach the Moluccas.

Here is the list collected in The life of Ferdinand Magellan, and the first circumnavigation of the globe. 1480-1521 by Hill:

20 quintals of quicksilver.
30 do. vermilion.
100 do. alum.
30 pieces valuable coloured cloth at 4000 ms. per piece.
20 lbs. of saffron.
3 pieces " veintenes," ^ silver, red, and yellow. (Pieces of cloth containing 2000 threads to the warp. )
1 piece Valencia stuff.
10 quintals of ivory.
2 pieces of coloured velvets.
200 common red caps.
200 coloured kerchiefs.
10,000 fish-hooks.
1000 maravedis- worth of combs.
200 quintals of lump copper.
2000 brass bracelets.
2000 copper do.
10,000 bundles of yellow matamundo (?).
200 small brass basins of two sorts.
2 dozen large basins.
20,000 small bells of three kinds.
400 dozens of German knives of the commonest kind.
40 pieces of coloured buckram.
50 dozen scissors.
900 small looking-glasses, and 100 larger size.
100 quintals of lead.
500 lbs. of crystals, which are diamonds of all colours.

As we see, there is abundance of different stuff. Some metals (alum, copper..) and textiles (red caps, kerchiefs, velvets) and lot's of small trinkets (fishing hooks, bells, combs, bracelets, knives, scissors, eye-glasses) that proved very popular in the Americas, Africa and smaller islands of Pacific and East Indies but which were somewhat useless in developed markets of India.

Some of this stuff was mostly intended as samples to be given or shown to locals to show what future trade can bring if the locals accept this trade

Thank you very much for your comment. Two things ive wondered, how often were the Portuguese ships (or others) using force or piracy to fill their ships? Was peacful trade vastly more common than basic brute force and plundering of vulnerable targets (on land or sea)?

Also, were people intended to be sold as slaves a part of this trade at all? Not thinking of African people but people rounded up and forced on ships following european conflicts or clearing land etc. Or was human cargo for sale, subject to die easily on board and/or just not valuable enough? Was the human trafficking taking place more on land trade routes?