What DLC has the most contracts on the bounty board?

I need to know because I need the most key contracts out of a day.

The contracts are tied to maps. You can get a total of 6 contracts a day, and they appear to be randomly selected from the total amount of maps available (not just the ones you own). I believe 3 are always from the base game, but I'm not 100% sure, so the other 3 will come from DLC. The DLC add the following maps:

• Schluesselschloss adds only a single map, The Last Stand
• Karak Azgaraz adds three new maps: Khazid Kro, The Cursed Rune and Chain of Fire
• Drachenfels also adds three new maps: Summoner's Peak, Castle Drachenfels and The Dungeons
• Stromdorf adds only two new maps: The Courier and Reaching Out
• Death of the Reik also adds only two new maps: Reikwald Forest and The River Reik

Therefore, Karaz Azgaraz and Drachenfels would be the best DLC to get, to give you the most new quests; however, they are more expensive than the ones that give two maps, so that may be something to consider.