I think it would be best for you to figure out the differences between monsters and why they are included in stories. Rather than creating a buffet and slapping them into a novel.
Monsters are a plot tool.
For example, in LitRPG monsters are used to make a plot move forward and accelerate character progression.
It's a good idea to ask yourself why you feel the need to include monsters. Are they an obstacle to overcome? Do they make the character a better person? Are they there for flavor? Or are they integral characters on their own, with backstories, feelings, and dreams?
If so it becomes easier to conceptualize what monsters you want if you know their purpose. if you want something dark and foreboding maybe a dragon or a skeleton/necromancer. If you want something cute, maybe a horned rabbit beast or an honest to god cat girl. If the character is fickle and vindicative, maybe make them a demon or kitsune. Do you want something wild and foreign? Consider a wolf-type monster or a fox.
Monsters give story flavor but it's better to consider what purpose the monster has to the story. In general, I tend to avoid monster stereotypes and ask myself what would make the most sense. It's why my dwarves are femboys and my elves are Ara Ara muscle girls.
Yeah I definitely agree with this approach, empty stereotypes are bad and you shouldn't put them in just because you feel you need different races. However, you can still use some of the stereotypical traits and make something reasonably interesting from them.
The process I use for making races is that I usually use them to highlight racial and cultural dynamics. I like to put in some traits and then think about how this will affect them as a society.
Take your stereotypical Elvs, they live long lives and love their forests. So I added the trait of having a long pregnancy period of three years and their forest pretty much provides all the resources they need in an almost infinite supply. As a result, their culture is very different from human culture, which means they are also organized very differently as a society.
In my story due to the fact that they need 50 years to become an adult and the fact that pregnancy lasts so long they replenish their numbers extremely slowly. So in a fight, they prefer ranged tactics like using mounted archers and ambushes inside their forest to reduce casualties. (Which plays into the whole elven archer and forest dweller stereotype) I also added traits like they are good with healing magic because again they need to preserve their wounded.
Also as a society, the elves in my story do not use any form of monetary currency in their society, they just ask a tailor if they need clothes and the tailor makes some for them. If they need food they just pluck some fruits. If they need healing they just find a healer to ask for healing. The reason for this is that the forest gives them all the resources they would possibly need, there is no scarcity. When there is no scarcity then supply-demand economics cannot function which means money doesn't really serve a purpose in their society. This also by extension causes the Elves to dislike the humans and dwarves because they view them as greedy since they like to hoard resources for themselves. Which leads to cultural friction between the races.
Another trait I added was that the Elves can obtain the memories of the flesh of the things they eat. So if they eat too much meat they can go crazy from all those extra memories. So they are vegetarian and they also eat the flesh of their dead family to keep a "piece" of their loved ones within them. This of course is disgusting to humans and is taboo since humans can get diseases from cannibalism, which eventually manifested into a cultural taboo.
So if you take the traits a make sure that these traits impact the way the different races behave and think you can avoid the problem of having Elves just being long-eared humans. Alot of stories just basically have long eared humans(Elves), short humans (Dwarves), strong green humans (Orcs), etc...
I would suggest looking into your story and decide if you have any plans for these races. Decide how they are going to impact the story and then build their entire society and biological traits from the ground up to create a believable group of creatures that feels organic and realistic.
