Ruby would be an obvious choice. Since they are both friends in the RWBY series, a crossover could explore a deeper bond between them. Maybe they go on a special mission together that takes them to a new and dangerous part of Remnant. Another good character could be Weiss. Their different personalities and fighting styles would create interesting interactions. Weiss' ice powers combined with Penny's technological abilities could make for some cool combat scenes.
One common theme is friendship. Despite their differences, many fanfictions explore how Mercury and Penny could form an unlikely friendship. Another theme is redemption. For Mercury, who has a rather complex and often villainous role, fanfictions may show him on a path of redemption with Penny's influence.
Well, a great concept for 'rwby penny crossover fanfiction' is Penny getting a power upgrade from an unexpected source. Maybe she encounters an ancient relic that gives her new abilities. She could then use these to help the RWBY team in a more significant way. For example, she might be able to communicate with Grimm and understand their motives, which could change the whole dynamic of how the RWBY gang approaches fighting them.
One popular rwby mercury and penny fanfiction is 'Mercury and Penny's Unlikely Alliance'. It explores their relationship in an interesting way, with unique character interactions and a plot that keeps you engaged.
One popular 'rwby ruby x penny fanfiction' might be those that focus on their friendship. For example, stories where they go on adventures together in the world of Remnant, facing Grimm side by side. They could be exploring new areas and learning more about each other's abilities.
You can start by looking on fanfiction websites such as Archive of Our Own (AO3). It has a large collection of RWBY - related fanfictions, including ones about Ruby and Penny. Just use the search function and type in 'rwby ruby x penny' and you'll likely find a good number of results.
In ancient times, a copper coin was worth one coin. In ancient China, coins were divided into different characters, such as Wen, Wu, Xuan, Huan, Bao, etc. Each character represented different values and uses. The word "Wen" represented the face value of the copper coin. And "one point" referred to one hundredth, which was usually used to indicate the weight or volume of small items. Therefore, in ancient times, a copper coin was worth one coin.
Penny is the person whose story is being told in 'my 600 pound life penny's story'. She is probably a person who has been struggling with her weight, which has reached a significant amount, likely 600 pounds. Her story may cover various aspects of her life, including how she got to this weight, her daily challenges, and her attempts to change her situation.
It basically means that every penny you save is as valuable as earning one. In a story, it might show the importance of being frugal and careful with money.