Below is a list of the garrison Bounty quests. These are obtained from visitors to your garrison - each day you have a 1 in 5 chance of getting a Bounty quest NPC. Other possibilities for visitors include [npc=89793], a trade vendor, a dungeon quest NPC, or a raid quest NPC. The bounty quest NPC is [npc=89806] (Horde) or [npc=89805] (Alliance).
You can visit the garrison of friends who have the bounty quest NPC to get the quests (or use the group finder if people have been kind enough to list groups with this NPC).
[npc=89843]
Spires of Arak
[npc=89827]
Frostfire Ridge
[npc=89825]
Shadowmoon Valley
[item=122191] has a chance to drop from the mini-bosses that are the target of the daily Bounty quest. This includes [npc=90070], [npc=89825], etc. as per the chart above. When it drops, only a single [item=122191] drops per group (rather than for every group member). However, the 3 Ring of Blood Invitation inside can be distributed by the person receiving the stack.
Each of the [item=122191] contains 3 Ring of Blood Invitation. The Ring of Blood Invitations are BoE and can be sold or traded on the Auction House.
The Ring of Blood Invitation initiates a quest (The World Famous Ring of Blood!) that involves killing 5 opponents in the Ring of Blood, and rewards [object=240071], containing gold, [item=32572]s, and follower upgrade tokens/follower armor sets.