COVID Tracker vs. JHU

As of May 31, there were 5,845 more deaths reported by JHU than by COVID Tracker. The last time JHU's death toll was not higher than that of COVID Tracker was March 15, when the former  exceeded the latter by just 6 deaths. March 29 was the last time JHU's death toll exceeded that of COVID Tracker by less than 1,000 deaths (in that case, the difference between the two was 991 deaths).
The Pearson correlation between the number of deaths reported by COVID Tracker and JHU was 0.9996166.

COVID Tracker vs. NYT

As of May 31, there were 5,845 more deaths in the US reported by the NYT than by COVID Tracker, and the last time that COVID Tracker reported more deaths nationally than NYT (as well as the last time NYT did not report more deaths than COVID Tracker) was over two months earlier on March 17, when COVID Tracker reported 3 more deaths nationally than NYT. Every day since (and including) April 5, the NYT's death count has exceeded that of COVID Tracker by at least 1,000 (meaning April 4, when NYT's death count exceeded COVID Tracker's by 979 deaths, is the last time that NYT's lead over COVID Tracker in this regard was less than 1,000 deaths). 
The Pearson correlation between the number of deaths reported by COVID Tracker and NYT was 0.9997858.

COVID Tracker vs. USAFacts

As of May 31, there were 4,489 more deaths in the US reported by USAFacts than by COVID Tracker, and the last time that USAFacts did not report more deaths nationally than COVID Tracker was March 17, when the two trackers reported an identical number of deaths. (The last time COVID Tracker reported more deaths than USAFacts was two days earlier, March 15, when it reported 5 more deaths than USAFacts.) As with the NYT (as noted just above), USAFacts' death count has exceeded that of COVID Tracker by over 1,000 every day starting April 5. The last date when this excess was less than 1,000 was April 4, when USAFacts reported 906 more deaths than COVID Tracker.
The Pearson correlation between the number of deaths reported by COVID Tracker and USAFacts was 0.9998093.

NYT vs. USAFacts

As of May 31, there were 778 more deaths in the US reported by NYT than by USAFacts, and the last time that NYT did not report more deaths nationally than USAFacts (as well as the last time USAFacts reported more deaths than NYT) was April 10, when USAFacts reported 133 more deaths than NYT.