I use two accounts for email, one for contacts. I see all 3 in Gmail app, but only want to see 2. Is there a way to only see my email accounts as choices?
According to Gmail support, accomplishing this without explicity removing it from device is not possible:
To remove the Gmail account only from the Gmail App isn't possible. If you do not want that account to be available in the Gmail App, the only way to do that is to remove it from your phone's device settings.
If your device has xposed framework, you can use xprivacy to hide any account to specific applications, there is no other way for hiding from official gmail Android client.