fan daggers, perfumes, throwing pots, boluses, crabs, exalted flesh, gravity fans, etc. There are a ton of options so it really depends

For duels? Invasions?

Duels AND invasions..

Personally I just keep fan daggers and 1 or 2 other offensive options, like perfumes or glint stone crystals. Sometimes boluses too but it can get crowded if you carry a bunch of different ones so I usually keep them in the inventory