The ornamental design for the billiards training set, as shown and described.
FIG. 1 is a top plan view of a billiards training set having a right and a left cut shot, showing my new design;
FIG. 2 is a bottom plan view thereof;
FIG. 3 is a right-side elevational view thereof;
FIG. 4 is a left-side elevational view thereof;
FIG. 5 is a front elevational view of the left shot cut, shown separately for ease of illustration;
FIG. 6 is a rear elevational view of the right cut shot, shown separately for ease of illustration;
FIG. 7 shows the right cut shot separately for ease of illustrating and in its environment of use; and,
FIG. 8 shows the left cut shot separately for ease of illustrating and in its environment of use.
The broken lines in FIGS. 7 and 8, including the broken line circles on top of the cut shots, depict environmental structures that form no part of the claimed design.