Depending on the trinket, some don't have a use at the moment, others can be used in site activities like hunting or crafting.
For trinkets that you should keep, i use This guide! (kinda image heavy to me, you probably have to use ctrl/f or the 'find' tool to search what you need, specifically page 2)
For those trinkets with no use, you can keep them if you want, but if you want to complete achievements like: 'Best I Can Do Is 20 Pebbles'(<< sell items from inventory), you can sell them!
A few trinkets are used in the Hunting Profession, such as: Common Hunting Trophy, Wanderer's Charm, Nomad's Luck, etc. I'm sure there is a list of the hunting specific trinkets somewhere in the forums. You accumulate the lower rarity ones pretty fast, so I regularly sell trinkets that I have over a 100 of.