Yes, on the condition that the license for every piece of graphic you use allows it.
Adding to what Yal said, you can use someone else's assets so long as you follow there license agreement which is often just things like 'give credit', 'dont claim/miss-represent the IP', 'dont re-distribute the IP in a way that violates this EULA', etc.
If your making a commercial product tho(which you probably aren't...), then you should do a bit more research and probably contact the IP owner directly, as things always get a bit messy when commercial production is involved or money is to be made.
edit: Also, if a asset doesn't have a license attached to it, then that doesn't mean you can use it without any limitations, the license is what gives you specific permissions, not the other way around.