The Monrad system still appears to be in use. What makes Monrad attractive is its element of randomness, whereas Swiss pairings can easily become monotonous when the same players participate in tournament after tournament. Monrad is particularly well suited to rapid and blitz chess, but in more serious competitions the system can result in less equitable pairings.
For this reason, I have developed a hybrid of the Monrad and Swiss systems: [Club Swiss System](https://mats-winther.github.io/club-swiss.htm). Claude (AI), which assisted me in the process, considers it a sound solution. Players are divided into three rating groups, each of which is randomized separately. The system combines the variety and unpredictability of the Monrad system with the competitive fairness of the Swiss system, making it especially suitable for chess clubs. During the first two rounds, the strongest group is paired against the middle group, while the lowest-rated group plays among itself. After that, the entire field is paired as a single group.
The randomization admittedly reduces competitive fairness to some extent. However, all players in the strongest group face opponents from the middle group during the first two rounds and receive the same color allocation. Having the lowest-rated group play among themselves at the outset also makes the tournament more engaging for them. At the same time, it gives them an opportunity to move up the standings at an early stage.