As for my fantasy, it is called "Meleenas Adventures - Treasure Of The Umbrunna."
The MC is Meleena, she goes on an adventure, and it is designed with the intention of being a series.
My adventure thriller series is what I call the "Gold" series. Lusitania Gold, Spanish Gold, Palmdale Gold, etc.
On the other hand, my icky bug novels all have "The" titles, so far. "The Greenhouse" and "The Factory." I decided on the "The" titles a long time ago. I recently realized that horror writer Bentley Little uses the same pattern. I haven't noticed it so much with other authors.
I think my titles fit the stories like a glove. However, an agent might not. I'll cross that bridge when I come to it.