Previous solution:
ant, ants, apt, asp, ats, nap, naps, pan, pans, pant, pants, pas, past, pat, pats, san, sap, sat, snap, spa, span, spat, tan, tans, tap, taps
ant, ants, apt, asp, ats, nap, naps, pan, pans, pant, pants, pas, past, pat, pats, san, sap, sat, snap, spa, span, spat, tan, tans, tap, taps