I want to know which gifts I should hang on to and, by exclusion, which gifts can be sold to merchants without fear of having to re-buy them to appease that one snotty NPC.
So far I've seen the following:
1st act
- Trish: Trish's potion (obvs)
- (Buxom) peasant woman in the village on the outskirts of Vizima:
Tulips (A corpse in the area will have them). Reward: good time. - Beggar woman living in the village on the outskirts of Vizima: White Gull, will reward with Eternal Fire signet ring.
- Old woman living in the village on the outskirts of Vizima who doesn't talk to strangers: Unknown, will accept bribe. Rewards with a story.
- Woman in white dress living in a house on the outskirts of Vizima:
Wild flowers, will give Tulips as reward. - Old woman living in the house opposite of the chapel: Any food (Bread
is most cost-effective), will tell a story, possibly giving some
glossary entries. - Vesna, after completing her quest, at the mill: any wine. Reward: good time.
Act2
- Jethro, at the dungeon: Fisstech, rewards with information. useless unless part of a quest.
- Gardener at Vizima's temple: any food, will reward with a tale or roses of any color you choose. Repeatble.
- Herbalist at the market of Vizima's Temple district: Red shawl. Reward: information about where she gathers herbs. useless.
- Bootblack, near where you emerge from the sewers in Vizima: Shadow People, or the story of His Majesty's Secret Service. Get the book by outdrinking Thaler. Reward: Prophet Lebioda's signet ring, useful for getting past Shani's landlady.
Best Answer
The best resource for this is the Shopping List over at the Witcher Wikia.
The 'condensed version', totaling up all of the various by chapter lists, provides these aggregate numbers:
If it's not listed above, or you've already made use of one, and you don't have a use for it yourself, you can safely sell it. Consult the Shopping List link above for a more detailed chapter by chapter breakdown of which items are useful where and when.