Lucky for you there are a bunch of options from paid to free.
Starting off there's Plant that has free and pro tiers and is in open beta.
Next there's Abstract which also has free and pro tiers and is also in open beta.
Additionally Folio exists but it's not as solid of an option in my opinion as the others.
Finally there's my favorite which is Kactus; which also has a nice github page.
Now what you chose all comes down to your workflow.
Abstract is good if you are already familiar with Git. Abstract also does a nice job at visualising the timelines and "commits".
Kactus works to bring together designers and developers onto a shared
workflow and platform in GitHub. Kactus aims to bring designers on
board to have an integrated design process
Plant, unlike Abstract and Kactus which use a branching model for
collaboration, only shows a linear history. Using the known
paradigm of uploading/downloading changes, Plant has created a simple
and elegant solution that would satisfy many people.
Find what you like and what works for your workflow!