Allstar
AllStarLink is a network of Amateur Radio repeaters, remote base stations and hot spots accessible to each other via Voice over Internet Protocol. AllStarLink runs on a dedicated computer (including the Rasperry Pi) that you host at your home, radio site or computer center. It is based on the open source Asterisk PBX running our app_rpt application. App_rpt makes Asterisk a powerful system capable of controlling one or more radios. It provides linking of these radio "nodes" to other systems of similar construction anywhere in the world via VoIP.

AllStarLink's primary use is as a dedicated computer node wired to your repeater or radio. Connections from Echolink, other VoIP clients and telephone calls are supported.
Link: https://www.allstarlink.org/

DMR
Digital Mobile Radio or DMR for short is an open standard or protocol for digital mobile radios defined by the European Telecommunications Standards Institute (ETSI) and are used in commercial products around the world. DMR was designed to allow for more bandwidth on a particular frequency.
Link: https://www.dmrfordummies.com/
RWK Code Plugs: https://files.k5rwk.net/s/CqzPt7MtpzT5jQ5

DStar

D-STAR is a multi-platform integrated tool for communication using D-STAR radios. With only a pair of radios (or an entire repeater stack) a variety of data transmission methods are supported, including:

Instant-message chat

Automatic beacon messages

File transfers with error detection

Structured forms

GPS position reports

And much more!

Link: https://www.icomamerica.com/lineup/amateur/d-star/

Fusion

System Fusion is Yaesu’s implementation of Digital Amateur Radio, utilizing C4FM 4-level FSK Technology to transmit digital voice and data over the Amateur radio bands. In the early 2000’s GMSK emerged in the Amateur radio market as the dominant digital mode, however in 2013 Yaesu introduced “System Fusion” which quickly became the dominating digital format in Amateur radio because of quality, reliability and enhanced performance in a wide range of environments.

Digital Communication modes have gained popularity over the years in the market because of superior performance in environments with interference, noise and other contributing factors that degrade the quality of a standard FM Analog signal. Narrower bandwidth and the need for increased spectrum have led to the development of digital communications technology, which has been widely adopted in the Public safety and private business sectors that use two-way radio technology. Unlike it’s commercial counterpart, System Fusion is an Amateur Friendly Digital Operating mode, straying away from some of the design considerations that make commercial solutions less appealing and more difficult for Amateur Radio Operators, providing a simpler interface and features that meet the demands and needs of the Amateur enthusiast specifically. Below you will find more information on this marvelous new technology, and how it can meet every operators demand and needs for a clear and simple Digital Experience.
Link: http://systemfusion.yaesu.com/what-is-system-fusion/

SDR
Software-defined radio (SDR) is a radio communication system that uses software to implement components that are usually analog hardware, like filters and modulators. SDRs are versatile and can be used in many wireless applications, including amateur radio.

VARA
VARA is a High Performance HF modem based on OFDM modulation. VARA Modem, brings state of the art Military grade technology to new and existing HF data.
Link: https://www.winlink.org/tags/vara