Not really. In the Patreon build you can talk to Dunny in the guild lounge for more lucrative quests, but in the free version, I'm afraid all you can do is get Vulfox's Favor from him after you've finished all nine quest guild quests in Piratetown at least once, and then do the 3-stars quests repeatedly. If your Adventurer and Fucko are powerful enough, I'd say just do the missing heart quest over and over. Otherwise, if you wanna be quick, I'd say do the Tangled Cables quest. Yes, that one's only 2 stars, but with Vulfox's Favor in your inventory, it still gives you 8 QC each time.