In the galaxy the following melee weapons are relatively easy to obtain. Melee weapons are often allowed in places where other weapons are not allowed. None of these weapons can pierce the skin of a space ship. Melee weapons are often used to repel boarders.
Available in every culture (with the appropriate TL)
+1d6 Hand-to-Hand, Armor Piercing and Penetrating, Not vs. physical armor
1d6 KA, 6 STR Min
1/2d6 KA, 4 STR Min
+2d6 Hand-to-Hand, 8 STR Min
3d6 EB AVAD (Power Defense), 16 Boostable Recoverable Charge, 1m stretching
Racial Melee Weapons
Minbari Fighting Pike
+4d6 Hand-to-Hand, 10 STR Min, +1 OCV, 1m reach, Shrinks to 5 inches
Only for Minbari or Rangers
Narn Katak (Broadsword)
1.5d6 HKA, 12 STR Min, 1m reach
Centauri Coutari (Short Sword)
1d6+1 HKA, 10 STR Min, 1m reach
Anyone who is not a member of the Ranger or a Minbari will find themselves being confronted by other Rangers and Minbari, which usually doesn't go well for anyone not well trained.