While this could be a good idea/list in some users' view, some others may consider it off-topic, since it contains also bounties paid in altcoin

Also, while I don't know if Bitcoin bounties are centralized anywhere, we do have Overview of Bitcointalk Signature-Ad Campaigns and in time altcoin bounties get centralized by this or that user, depending on who's active and willing to do it. list of bounties good quality (new update 17_07_2021), despite the date in the title, was last updated less than one week ago.