Add in /etc/apt/sources.list:

Jessie:

deb http://apt.jurisic.org/debian/ jessie main contrib non-free

Stretch:

deb http://apt.jurisic.org/debian/ stretch main contrib non-free

Keyring:

wget -q http://apt.jurisic.org/Release.key -O- | apt-key add -


Source: Oracle Java 8 JRE/JDK

apt-get install oracle-java8-jre
apt-get install oracle-java8-jdk

Source: Discord

apt-get install discord

Source: WPS Office

apt-get install wps-office

Source: NextCloud

apt-get install nextcloud-server
apt-get install nextcloud-client

Source: Remmina

apt-get install remmina