Trademark rights are territorial, with over 200 national trademark registries and a few multi-jurisdictional systems, like the pan-European Union system called the Community Trademark.
There are several different databases and techniques for “clearance,” which refers to determining whether a name can be used with a low likelihood of infringing the trademark rights of others.
Because trademark infringement involves so many ambiguities no clearance can provide certainty, so instead the goal is to reduce the risk of infringement to a tolerable level.
A trademark lawyer can do a clearance for you.
At some point it would be difficult to change the name throughout your entire project if you receive a complaint from someone claiming you are infringing. With a growing user and contributor base, it makes sense to have more assurance you can use your name into the foreseeable future.
This is probably the time to consider a more formal legal clearance process for your name. You also should consider whether it is the right time for registration of your trademark to formally establish and document your trademark rights.