The above posters have already given really great information/ideas, but I'll just toss some stuff in because I do work with bones. As an animist, I believe it's important to check with the animal and see if it's okay to use their bones, but that depends on your beliefs.
Here's a forum post I wrote on bone reading that tells how to divine with and cleanbones: https://www.spellsofmagic.com/read_post.html?post=920804
You can use bones in spiritwork, as said above. You could also use them to tap into the energy of deer in general.
You can make tools from bones. I have a scapula I use to hold an offering cup and a bone wand. I've also used skulls and vertebrae as candle holders. You can also just use them to decorate your altar. It's a great way to draw in the energy of the animal and to allow yourself to connect with death energy. I like to use them to balance out my altar (some plants for life, some bones for death).
You can use them as talismans corresponding to the energy of the animal. For example, if you found the bones of a doe, you might find themto have a gentle, motherly energy. You could use this to help calm you during times of stress. (Just an example.) You could wear the talisman as jewelry if you wished.
You could also use certain bones in corresponding spells. If you cursed someone, for example, you could use teeth to give the curse some bite.
Some people use bone powder as an ingredient in various things. The purpose ofthis may vary depending on the recipe.
I've also found that sometimes you can sit and hold a bone and just feel out something to do with it. Not always, and it's totally fine if that doesn't happen with these bones, but I've had time where I pick up one of my bones and just feel like I should make a certain things with it or preform a certain spell.
Other than that, I think doing a ceremony for the deer sounds very nice. Whether you opt to use them in practice or not, I've found that doing a little thing to honor the animal that passed is nice, and it helps connect you to the process of gathering, cleaning, and working with the bones if you choose to use them.