As I posted in another thread only minutes ago, I believe this is your answer - yes there will be more calls, both official and built in to the game and community made content:

There are now a few additional calls in the workshop. 5 from Justu (3 with voiceover, 2 without), 9 from Linus (all without) and 2 from myself (1 with voiceover and one prank one without). I know that between myself and Linus more are coming and I hope others will join us too.
Check out all calls without voiceovers in this collection: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=932398926#
And all calls with voiceovers in this collection: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=932399694

If you've got any ideas or are willing to record some audio for a voiceover please contact me and I hope you enjoy the community ones found in the above collections. :)