I've been reading through a lot of questions re various races strengths and weaknesses in battle and social organisation & it made me think that there would be quite a few areas where different races in alliance work together quite well and offset individual races weaknesses so which races do you think work best together?
Dwarves and humans
Traditional dwarves live underground and spend most of their time mining and smithing. This creates a huge problem however: you can’t eat rocks. Living underground means little to no access to the sun, meaning most plants are unable to grow. There are a ton of ways to solve this issue that have been discussed on this site, but most of them involve giving them more access to the surface, or copious amounts of handwavium. The simplest solution, that keeps dwarves underground is trade
Now to support a decent sized underground city, they’d need to do a lot of trading, and be pretty dependent on surface dwellers. Humans on the other hand, in most fantasy worlds tend to be pretty basic compared to fantasy races. They often have little to no special abilities and live an extremely short lifetime compared to other Tolkien-esq races. This does give humans a pretty big advantage however: they move quickly. In the time a single elf could prefect sword making humans can create an entire sword producing factory, and schools to train new blacksmiths. These swords might not be as high quality as the elf’s but can be produced at a significantly faster rate.
This effect can be applied to every aspect of humanity. A single dwarf generation might live through several human generations. This means that humans are the perfect trading partners. They outpace dwarf population growth by so much that they will always be able to produce enough food for the dwarven settlements, and the humans can take advantage their advanced mining and smithing techniques.
So human settlements tend to follow the dwarves and almost every dwarven city has a human counterpart near by. Dwarves can eat and humans get cool metal and tools