Good question, if you play enough with debian you will finish making Debian packages. That's what happens to me, I use software that isn't on the oficial repositories, so I end up making my own packages. In this repository you can find all kinds of software for different architectures, some could be useful for you or not, but you do not lose anything if you try it.
Few but useful. All packages have been created for Debian 9 stretch in different architectures. You can find packages for amd64, i386 and armhf. So you can use it on you newer PCs (amd64) and other devices like Raspberry PI or C.H.I.P (armhf). If you are looking for a list of packages, you will not find it here, configure the repository on you system and list them all.
Well, is so easy, you have to add the address of the repository next to those you already have. To do it, open a terminal and type this command:
sudo nano /etc/apt/sources.list
Now go down to the end of the file and paste the next text:
# FoRTu.io debian Repository
deb https://apt.fortu.io/ stretch main contrib non-free
Save changes and exit pressing CTRL+X. The next step is to download the GPG key with which the packages are signed:
sudo apt-key add repo.key
Perfect, now is time to update all the repositories, including the new one:
sudo apt update
Let's try to install a new package. I made one with all the necessary files to serve a 'Quake 2 Team Deathmatch' server. So you can see all the information about the package by running the following command:
sudo apt show quake2-opentdm-server
As you can see in 'APT-Sources' this package is in my personal repository, and can be installed in the same way as any other package:
sudo apt install quake2-opentdm-server
sudo apt purge quake2-opentdm-server