Mapora is an open-source georeferenced point cloud generating tool. Basic idea is putting each individual point cloud onto the pose which are matched with time in nanosecond precision.
Additionally, Mapora has a rosbag parser tool for generating point clouds with rosbags.
One of the important point for exporting tightly coupled point clouds with Mapora is having high accurate GNSS/INS positions. To provide that, it is highly recommended to use a post-processing software for GNSS/INS positions.
The other important issue is having precise LiDAR-IMU calibration angles. If not, the possibility of having bad features in map is very high.
Some of the views of the point clouds can be seen below.
Mapora has 2 different executable. One of them is working with specific sensors with post-processed GNSS/INS data and the other works with rosbag includes PointCloud2, NavSatFix and Imu topics.