4 letters:
balk, barb, bard, barg, bark, bart, card, carp, cart, dark, dart, garb, gard, garg, garp, kalb, kalp, karg, karp, parc, park, part, talc, tarp, tart

5 letters:
balkh, barbe, barch, barde, barke, calpe, carb-, carde, carpe, carte, darke, dartt, galpe, garbe, garch, garde, guard, karch, kharg, parde, parke, parte, tared, tarte, tartt

6 letters:
barque, barred, calque, dahlke, dolled, garred, parred, tarred