I want to type Symbol of aplha but I couldn't figure out how to get it , however I can type ß(Beta). But not alpha.
If you have superuser(root) access, install xposed framework. Search for an xposed module called 'Google Keyboard Custom Smilies' (GKCS) and install it. Open GKCS app and add 'α' symbol in it. You can use your own labels for inputs.
Use greek language.
Tap and hold space button for quick accsess.