Shifter

Shifters are one of the races to come out of the Eberron setting, alongside the Changeling and Warforged and oft-forgotten Kalashtar. The basic idea is that they are werebeasts-lite, having similar shapeshifting into beast powers without being as utterly broken as true lycanthropes. It's commonly believed that they are the descendants of humans and lycanthropes, hence the watered down shapeshifting power.

Initially, they weren't very popular, perhaps because the art made them absolutely butt-fuck ugly. Seriously, even your typical furry wouldn't bang the Eberron corebook shifters. Perhaps noting the attempts by fans to redraw them as monstergirls, WoTC prettied them up in subsequent art and they steadily grew more popular, though Warforged have always beaten them out.

Weren't in the 5e player's guide, but were part of the Eberron web-enhancement Unearthed Arcana, which can be found on the WotC website if you're willing to sniff around.

Saurian Shifters

Although Shifters kind of got ignored for most of Eberron's publication, Dragon Magazine did throw them a few bones. Perhaps the biggest of which was the Saurian Shifter variant race in Dragon #328, which replaces the mammalian traits/origins of the classic shifter with saurian ones. Or, in other words, it turns the shifter race into a way to play your choice of were-dinosaurs, which is either awesome or the stupidest thing you ever heard of, depending on who you ask.

Ability Score Modifiers: +2 Constitution, -2 Intelligence, -2 Charisma

Racial Classification: Humanoid (Reptilian, Shapechanger)

Size: Medium

Base Land Speed: 30ft

Low-Light Vision

Racial Skill Bonus: +2 to Balance, Climb and Jump checks.

Shifting (Su): Each saurian shifter has one dinothropic lineage, chosen from the list of seven below. This choice is set at character creation and cannot be changed afterwards. Once per day, the saurian shifter can tap into this lineage, gaining bonuses dependent on their lineage. Shifting is a free action and lasts for a number of rounds equal to 3 + the saurian shifter's Constitution bonus (using the increased bonus caused by any Constitution boost gained from shifted form, if appropriate). As with normal shifters, a saurian shifter can increase this duration and how readily it may take shifted form by taking Shifting Feats; shifting duration increases by +1 round per Shifting Feat taken, whilst every 2 Shifting Feats taken increases the amount of times a saurian shifter can shift each day by +1. If shifting grants a natural attack option, a saurian shifter may only make one natural attack each round, even if they have a base attack bonus high enough to grant multiple attacks.

Favored Class: Ranger

Saurian Shifter Lineages:

• Beasthide +2 Constitution and +2 natural armor bonus.
• Broadwing: +2 Dexterity, ignore the first 40 feet of a fall.
• Junglerunner: +2 Dexterity and increase base land speed by +20 feet.
• Longtooth: +2 Strength, grow fangs that bestow a natural attack (bite) that inflicts 1D6 + 1 per 4 character levels damage. A shifted Longtooth can make its bite attack as a secondary attack with a -5 penalty.
• Raptorleap: +2 Strength, +4 to all Jump checks, always counts as having a running start for Jump checks.
• Razorclaw: +2 Strength, grow claws that bestow a natural attack (claw) that inflicts 1D4 + 1 per 4 character levels damage. A shifted Razorclaw can make an attack with one claw as a standard action or with both claws as a full-round action (in both cases as a primary natural weapon). They can also use their claw as a secondary attack (light off-hand weapon), with a -2 penalty.
• Widetail: +2 Constitution, grow a powerful tail that bestows a natural attack (tail slap) that inflicts 1D6 + 1 per 4 character levels damage. A shifted Widetail can make its tail slap attack as a secondary attack with a -5 penalty.