It's always a bit tricky to find names for everything when you are mapping out a new corner of your campaign world. In real life, place names grow and develop from all manner of things - visible features, names of local landowners, corruptions of older languages - yet when you are mapping you have to just pull them out of a hat.
So here's a helper - a list of an hundred names for places. You may like them, you may even be amused by working out why the name you have rolled (or picked) is appropriate for the place you have assigned it to...
The good thing is most of them sound reasonably plausible. The downside is that they are listed alphabetically, rather than by the type of place... so if you know you are looking for a name for a stream, you cannot check 'stream names' but have to search for the ones that are... or of course, take any name and decide that it is a stream name rather than the island or jungle name that it's given as.
The best use is that it's a good way to get your own creative juices flowing. Just read it and you'll start coming up with your own variations... get your map out and get busy!