This list is in no particular order and I do plan to update it as I find other sites of interest.
The folks who run the Brandmeister Network offer interesting network statistics at the Brandmeister Dashboard.
N0GSG has developed free software called Contact Manager where you can maintain code plugs from various vendors all in a single app. Code plug conversions between radios are also possible. As of this post Contact Manager works with the CS700/750/800 Tytera MD380/390/390GPS, Retevis RT3, and AnyTone AT-D858 Radios.
W2XAB published a rather comprehensive PDF in 2015 called the Amateur’s Guide to Digital Mobile Radio. It’s worth the read for anyone interested in learning more about DMR.
K2YO and the Long Island Mobile Amateur Radio Club presented an Introduction to DMR which does an excellent job of covering DMR for the newbie.
KC5HWB is the creator of HamRadio 2.0. As of this post, Jason has published around 90 videos. Many of his videos cover reviews of various DMR radios, code plug programming and HotSpot reviews. If you want to purchase ham radio equipment, check out Jason’s ham radio store at Grapevine Amateur Radio.
The PRN System offers a Wide Area Digital Amateur Radio Network which spans areas of North and South Carolina as well as areas of Virginia. Their Web Site offers a Getting Started Page, Repeater and Talk Group Information, Code Plug downloads and more!
KC7JOE’s blog has detailed information Fusion, DMR, DSTAR and HF NETS. Check out his Amateur Ham Radio Net List.
N2NSA has detailed information related to repeaters which connect to the New York Metro DMR Repeater Network.