Have excess karma, and don’t know what to do with it? While you could wait for seasonal vendors to appear, or spend at Karma vendors say in Path Of Fire locations for crafting materials, there is a second map currency dependency.
Another alternative is a bit more of a work around but directly exchanges karma for re sellable goods. Namely the Pact Supply Network merchants provide Map bonus items that can be used on a weekly Tyrian rewards track (see https://wiki.guildwars2.com/wiki/Pact_Supply_Network_Agent). These vendors, I believe, do require a Central World Supply Pact Mastery unlock, so you’ll want to train related mastery track.
In GW2 game chat window, type /wiki mbrp or go to https://wiki.guildwars2.com/wiki/Map_bonus_reward/profit
There is a bit of map hopping (6 locations for the daily map bonus items), and then hopping to the desired map location for the weekly profit (maximum). Also to take advantage of map bonus rewards, you’ll want to work map completion, but on the weekly, this can translate into a profit of up to extra gold (e.g. for instance 17 gold in one location recently checked). The map bonus reward resets (per guide) weekly on timer after accumulation of 8000 rewards points. Each map bonus reward item provides 200 bonus points or 1200 points daily with all 6 bonus map items.
If you don’t cash in on rewards crafting materials, you could alternately save these for legendary crafting. This usually takes no more than 15 minutes using guides for completion per day.