Kari Nurmela and Patric Ostergard wrote a simulated annealing program was used to quickly construct many of the coverings.
Another program that generates good coverings is Ininuga, which produced many coverings in the tables.
Alex Sidorenko has contributed many coverings and several general methods based on his work in Turan theory.
Greg Kuperberg noticed that complements of linear [v,t] codes give variable block-size (v,*,t)-coverings, which led to a number of improvements.