Well, in the Lotr story, there are female Dwarfs. Their existence is somewhat in the background. The Dwarfs were a race that was more often presented through their male counterparts in the story. But we know that they had a role in the continuation of the Dwarf race. They were likely involved in teaching the young Dwarfs, maintaining the traditions within the hidden mountain kingdoms, and also in some of the more domestic aspects like food preparation and the making of clothing and other items necessary for life in the Dwarven communities.
One of the great ones is 'The Grey Wanderer'. It beautifully weaves the magic of Middle - earth and the wizarding world. It has a unique plot where a character from LOTR somehow ends up in Hogwarts and the interactions between the two universes' elements are just amazing.
Morgoth might see Yavanna as a threat to his dominion in fanfiction. He could attempt to undermine her work by spreading blight on the lands she nurtured. Yavanna would surely retaliate, perhaps by using the power of the growing things to bind Morgoth's forces.
One possible plot could be that the violinist is a half - elf who uses the power of music from their violin to soothe the minds of those affected by the dark forces. They travel with the Fellowship, playing their violin to keep morale high and to counter the psychological attacks of the enemy.
It's hard to say there are really 'popular' themes specifically for pregnant and orc LotR fanfiction as it's a rather niche combination. But perhaps a theme could be the challenges of an orc pregnancy in a world filled with war and danger like Middle - earth. Another could be the acceptance or rejection of a pregnant orc within orc society.
A prevalent theme is the exploration of different forms of magic and science. The Doctor's scientific knowledge is juxtaposed with the magic in Middle - earth. There's also the theme of time, as the Doctor is often associated with time - travel. How does the concept of time in the Doctor's world interact with the more linear time (in a sense) of Middle - earth? This can lead to some really thought - provoking stories. Another common theme is the Doctor's role as an outsider trying to fit in and make a difference in a world that is not their own.
Female Dwarfs in the Lotr story have important but somewhat under - emphasized roles. They are crucial for the continuation of the Dwarf race through child - rearing. Also, they likely manage the internal affairs of the Dwarf - homes, such as storing food supplies, maintaining order, and passing on cultural traditions to the younger Dwarfs.
Sorry, I'm not aware of specific 'violinist x lotr fanfiction' stories. You could try searching on fanfiction websites like Archive of Our Own. They have a large collection of fan - made stories and you might be able to find something related to a violinist in the Lord of the Rings universe there.
Look for fanfic anthologies or collections that focus on crossovers. Sometimes, editors curate the best stories in these collections. You can also follow some well - known fanfic authors in the Harry Potter or LOTR fandoms. They might write or recommend great crossovers.