Please note: there are some minor spoilers for the 5th Edition conversion of Against the Giants in this article about trappings.
While reading the 5th Edition conversion of Against the Giants from Tales of the Yawning Portal I came across something that I’d personally done before but that I hadn’t seen in a published module—changing the “trappings” of a creature. It’s an ingenious solution to a tricky problem. You want to keep an encounter (or series of encounters) at a reasonable challenge level for the characters but you don’t want to make it look too easy. After all, a hill giant steading should be full of hill giants, right? But if every hill giant in the steading had a hill giant’s statistics it might be too much. The authors of the conversion instead choose to give some hill giants the statistics of ogres. It flows down as well, some of the ogres have orc statistics, while the orcs use the commoner statistics.
Like I said, ingenious. As it still makes them a threat but also allows the characters to feel heroic as they cut through swathes of them. It also means that players who know the Monster Manual inside out are kept on their toes. Another option is to make smaller changes to a monster. Change its maximum hit points, the weapon it uses or maybe even give it some spell abilities or a feat. A couple of single-use spells is an easy addition while also creating a bit more of a challenge for the characters. You can also do the same with a feat.
It works with other parts of the rules too. A sword of wounding for example, can easily become a staff of wounding if you prefer. Yes, the official rules state “weapon (any sword)” but such a change is unlikely to break anything. This works for a number of magic items: a hat of protection rather than a cloak of protection; and a cloak of invisibillity in place of a ring of invisibility. Likewise, with spells. For example, the magic missile spell. The official wording states “three glowing darts of magical force” but there is nothing wrong with changing the trappings to reflect the character better, whether that character be PC or NPC. An evil necromancer’s magic missiles could be flaming skulls for example.
This is something that generic systems like Savage Worlds highlight. The important element is that the trapping you add can’t change the power level of the ability. Consider it to be an extension of the character. Something that adds to the roleplaying element.
By way of example, is an alchemist character build I once looked at putting together. He was a spellcaster and used the standard spellcasting rules. However, the trapping of the character was that, each morning, he brewed up various concoctions (prepared spells) from his list of concoctions (spellbook). These concoctions took on the form of jars, vials and the like. The in-game result was the same as the spell, but the trapping was different. The character was still a wizard in game terms but now had a different feel to him that made him more unique.
Adding different trappings to the usual aspects of the rules as a player can help you come up with a unique and memorable character. Do it as a DM and you can keep the players on their toes.