Magic is often a strangely misrepresented thing in fantasy. It's almost solely aimed at combat and war, which is not how it would really go if magic were "real".
Magic would follow the same lines as technology. There won't be any fireballs thrown in the beginning. Instead the first magic that was discovered is about the 3 S's: Sex, Shelter, Sustenance.
Sex contains everything from making sure you look good to attract a partner, convincing said partner, getting pregnant, giving birth to a healthy baby and then continues with getting the child to grow up healthy and strong while teaching him things he needs to know.
Shelter contains everything from building something against the elements, from a small fire to keep you warm to the clothes you wear (or don't need to wear because magic) and everything around your home. Hell even just something to prevent your home from catching fire would be worth gold in ancient times.
Sustenance is all about the food. Finding it, making it, hunting it, protecting it, herding it, growing it, keeping it free from disease and poisons, preparing it, stockpiling it, keeping it fresh etc. It is likely that you would see magical refridgerators before you would see advanced weapons.
The items your mages leave behind are focused on this, and likely given to their children or those they care about. An artifact that can cure diseased crops, keep the soil fertile or even just harvest all the grains without harming the stalks so they can be harvested again would be invaluable.
An artifact that can cure disfigurements and change one's appearance to their wishes would be a most powerful tool in such times (it would be a powerful tool today!). Or what about a tool that makes people immune to certain diseases? Child death would go down, horrible diseases that we get shots for today would be eliminated (but what if the artifact causes autism? GASP!). Even if it can only be used for a single family, a powerful mage would not hesitate to give this to his own family so they can be strong and healthy for years to come.
Or imagine leaving something to improve the homes of your family? They could be fireproof, always a comfortable temperature without the need for heating or cooling, the space inside could be larger, furniture could be immune to wear-and-tear. It might not seem that powerful, but if you never have to replace your furniture in the olden times it save a lot of time, money and effort. Not to mention how it can increase the status of the family.
Most days aren't about warfare, and as miss Nightingale proved even war is less about the war and more about the hygiene needed so infections dont kill literal magnitudes more than the actual fighting does. Many wars never even happened because supplies are more important, and the ability to send home your troops so they can help with harvest is invaluable for the country as a whole. The amount of magical artifacts focused on warfare would be minuscule compared to the amount of magical artifacts focussed on just making it through to the next year.