Where are the quests that decrease bounty ?

[Crown]

Or is there no such thing.

Thanks

[quarre]

You can use decrease bounty vouchers that you can find in safeboxes in great quantity. Blue ones are kinda comon, and every of those decrease bounty for 500 gold. There's also purple (2000 gold) gold (100000 gold) ones, but i've seen gold only once, as reward for completing Thieves Guild quest line, and you cant store it in Bank to transfre to other characters.
https://esoitem.uesp.net/itemLink.php?itemid=71779
https://esoitem.uesp.net/itemLink.php?itemid=73754
https://esoitem.uesp.net/itemLink.php?itemid=73753

Blue and purple are fencing and stacking easily, so you can store tons of those without any harm, put in Bank and use on any of your characters. You can get those in other ways (like pickpocketig, but safeboxing is more profitable. Only bad thing is ZoS hates NB class, and since most of thieves are NBs, they nerf chests.

So you need Treasure Hunter bonus from CP (increase drop grade from chests, safeboxes and bosses). And CP skills from The Shadow are kinda useless (decrease sneak costs, decrease block cost and 2 other useless sh_t).

[< blank >]

There are things kinda like waiver which will decrease your bounty ( can be obtained from thief guild dlc ) also thieves guild passive allow you to get rid of the bounty faster. But the best way is to wait it out, as long as youre not going around killing npc youre fine.

[quarre]

You dont need Thieves Guild DLC to get those vouchers :3
Or you mean they implemented some weird merchant, who sell those? O_o

Thieves Guild passives are awesome, you can pass through small bounties in few mins. But its not cool if you want to get that "pay 100k gold for removing bounties" achievement, because with full guild passives it will take ages to xD

[Drake]

Just fence and launder whatever stolen stuff you have and kill yourself. There goes the bounty.