Traders

The Bog Witch

Her wares go into fishing:

Her ware	Goes into
Pungent Pebbles	Stinkbait (cauldron): catfish, trollfish, pike, mistfin and bass love it
Fresh Seaweed	Seaweed Chum (cauldron 2): more, keener fish for 6 minutes
Candle Wick	Lantern Float (workbench 2): use it and your line wears a candle-lit float for 20 minutes; fish bite 50% sooner at night
Love Potion	Spawning Musk (cauldron 3): legendary fish 50% more likely for 10 minutes
Powdered Dragon Eggshell	Major Steady-Hand Tonic
Toadstool	Major Troll-Grip Mead
Her herb blends	The fish feasts

Fish feasts are made in the cauldron and set down with her Serving Tray, like vanilla feasts, for everyone to eat from:

Feast	Cauldron	Herbs	Health / Stamina / Eitr
Lakeside Fish Fry	2	Woodland Herb Blend	40 / 40
Fin and Onion Hotpot	3	Mountain Peak Pepper Powder	55 / 50
Sea-Fish Spread	3	Seafarer's Herbs	50 / 60
Roe and Barley Platter	4	Grasslands Herbalist Harvest	60 / 70
Abyssal Ink Banquet	5	Herbs of the Hidden Hills	60 / 45 / 70
Ember Fish Platter	5	Fiery Spice Powder	85 / 60
Rime Fish Smorgasbord	5	the Deep North spice	90 / 75 / 35

She also sells Stinkbait, Lantern Floats and (after Bonemass) Spawning Musk, and each boss lure once you've beaten that boss, so a failed summoning doesn't mean hunting a new trophy.

Floats

Some items are floats: use one like a mead and your line wears that float instead of the usual one until it runs out. There's no slot to fill, and only one float at a time. The Lantern Float is the first; its candle lights up after dark.

Hildir

Fishing bounties. Hildir posts one bounty a day for a species you've caught: at least so heavy, sometimes caught in the rain, at night or Trophy-size. Hand the fish in from the trade panel for coins and bait. Your 5th, 15th and 30th bounties earn a Yule Hat, the Horn of Ægir and Megingjord, with a Thunder Stone at 10 and a Dverger Circlet at 20.

Lost tackle boxes. Three of Hildir's tackle boxes turn up in dungeon chests. Give one back (use it on her, or from the trade panel) and her shop gains more:

Box	Found in	Hildir starts selling
Mossy Tackle Box	Sunken Crypts	Bog-Dyed Fisherman's gear, Guck Crawlers, Leather Grubs
Frosted Tackle Box	Frost Caves	Frost-Dyed Fisherman's gear, Silver Swimbaits, Frost Bait
Dvergr-Mended Tackle Box	Mistlands dvergr ruins	Mist-Dyed Fisherman's gear, Bone Jigs, Abyssal Bait

The dyed gear is bought, not crafted, but repairs at the workbench (level 2) like the rest of the set.